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EDU-SPEB1-EnglishManual.pdf
EDU-SPEB1 EDU-SPEB1/M Advanced Spectrometer Kit User Guide
Advanced Spectrometer Kit
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Table of Contents Chapter 1 Warning Symbol Definitions ........................................... 2
Chapter 2 Safety ................................................................................ 3
Chapter 3 Introduction ...................................................................... 4 Chapter 4 Setup ................................................................................. 5
4.1. Components and Parts List ............................................. 5
4.2. Component Assembly .................................................... 8 4.2.1. LED Wiring ................................................................................ 10
4.3. Setup and Adjustment.................................................. 10 4.3.1. Light Source Setup .................................................................... 10 4.3.2. Prism Spectrometer Setup ........................................................ 11 4.3.3. Grating Spectrometer Setup ..................................................... 13
Chapter 5 Spectrometer Theory ..................................................... 15
5.1. Introduction ................................................................. 15
5.2. Wave Interference with Double Slits and Gratings ....... 15 5.2.1. Double slit ................................................................................. 15 5.2.2. Grating Interference .................................................................. 17
5.3. Dispersing Prisms ......................................................... 18
Chapter 6 Teaching Tips and Experiments................................... 21
6.1. Exercise 1: Wavelength Measurement of Three Lines in the Mercury Spectrum ................................................. 21
6.2. Exercise 2: Measuring the Index of Refraction of the Prism Using a Known Spectral Line ............................... 23
Chapter 7 Regulatory ...................................................................... 25
7.1. Waste Treatment is Your Own Responsibility ............... 25
7.2. Ecological Background ................................................. 25
Chapter 8 Thorlabs Worldwide Contacts ...................................... 26
EDU-SPEB1 & EDU-SPEB1/M Chapter 1: Warning Symbol Definitions
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Chapter 1 Warning Symbol Definitions Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
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Chapter 2 Safety
CAUTION Optical gratings can be easily damaged by moisture, fingerprints, aerosols, or the
slightest contact with any abrasive material. Gratings should only be handled when necessary and always held by the sides. Latex gloves or a similar protective covering
should be worn to prevent oil from fingers from reaching the grating surface. No attempt should be made to clean a grating other than blowing off dust with clean, dry air or nitrogen. Solvents will likely damage the grating's surface. Scratches or other
minor cosmetic imperfections on the surface of a grating do not usually affect performance and are not considered defects.
! !
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Chapter 3 Introduction Optical spectroscopy has made a major contribution to the development of today's concept of atomic and molecular structure and is indispensable as an analysis procedure in research and industry. Astronomers can analyze the composition of distant stars and environmental analysts can optically measure the composition of exhaust gases without having to take samples. Each of these application areas has different requirements with regard to the spectrometer to be used.
This kit includes parts to build two types of spectrometers, and can be easily set up by students. These spectrometers can achieve very fine resolutions, allowing very close spectral lines to be resolved, such as the sodium-D lines (spectral distance of 0.6 nm). As the setup is very small, LEDs can also be analyzed, although so-called "superbright" LEDs, which have a higher intensity than normal LEDs, are recommended. The included LED bracket makes it very easy to install the LEDs in the setup. Other light sources, such as incandescent lamps, energy-saving lamps (compact fluorescent tubes), mercury vapor lamps, and lasers can also be analyzed by the spectrometer
The experiment package contains the following wavelength-dispersive elements:
A reflective grating with 600 lines/mm. A reflective grating with 1200 lines/mm. An equilateral dispersing prism.
Additional gratings and prisms are available, which can be purchased separately from Thorlabs. Contact [email protected] for more information.
The supplied gratings are called blazed gratings, which means that the reflective layer is arranged diagonally. The great advantage of this is that the highest intensity is not in the zeroth diffraction order, which is directly in the incoming beam path and thus not of interest, but rather in a higher order, to the side of the incident beam. In the case of the gratings used in this kit, the first order is the most intense. However, you can also easily observe higher orders with the setup (up to 5 with the grating 600 lines/mm). In addition, blazed gratings function in the same way as normal gratings, so all of the standard grating calculations and equations apply. Thus, for teaching purposes, the difference need not be addressed, as there is no difference in the equations that are relevant for the classroom.
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Chapter 4 Setup
4.1. Components and Parts List In cases where the metric and imperial kits contain parts with different item numbers, metric part numbers and measurements are indicated by parentheses unless otherwise noted.
1 x LEDMF LED Mount
1 x LEDWE-15 Epoxy Encased White
LED, Package of 5 2 x ACL2520U Ø1" Aspheric Condenser
Lens, f = 20 mm
2 x FMP1(/M) Ø1" Setscrew Lens Mount
1 x LB1471 Ø1" Focusing Lens,
f = 50 mm 2 x LMR1(/M)
Ø1" Threaded Lens Mount
1 x VA100(/M) Adjustable Slit
1 x LB1676 Ø1" Imaging Lens,
f = 100 mm
1 x GR25-1205 1200 lines/mm Reflective
Grating
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1 x GR25-0605 600 lines/mm Reflective
Grating 2 x CH1A
Grating Mount
1 x PS858 Equilateral Dispersing
Prism
1 x KM100PM(/M) Kinematic Prism Mount
1 x PM3(/M) Clamping Arm for Prism
Mount 1 x EDU-VS1(/M) Viewing Screen
1 x MB1824 (MB4560/M) Optical Breadboard,
18" x 24" (45 cm x 60 cm)
1 x RDF1 4 Breadboard Feet 9 x TR3 (TR75/M)
Ø1/2″ (Ø12.7 mm) Optical Post, 3" (75 mm) Long
9 x PH3 (PH75/M) Ø1/2" (Ø12.7 mm) Post Holder, 3" (75 mm) Long
1 x TR2 (TR50/M) Ø1/2" (Ø12.7 mm) Optical
Post, 2" (50 mm) Long
1 x PH2 (PH50/M) Ø1/2" (Ø12.7 mm) Post Holder, 2" (50 mm) Long
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6 x BA1(/M) Post Holder Base,
1" x 3" x 3/8" (25 mm x 75 mm x 10 mm)
4 x BA2(/M) Post Holder Base,
2" x 3" x 3/8" (50 mm x 75 mm x 10 mm)
1x TPS5 Laser Safety Screen,
12" x 12" (305 mm x 305 mm)
Imperial Kit Hex Keys, Ball Driver, and Screws
Imperial Kit Hex Keys: 3/32", 0.050", 5/64", and 1/8" 1 x BD-3/16L
Balldriver for 1/4"-20 Screws
Imperial Screws: 10 x 1/4"-20 Cap Screw, 1/2" Long 12 x 1/4"-20 Cap Screw, 5/8" Long 4 x 1/4"-20 Cap Screw, 3/4" Long
12 x M6 Washers 4 x #1/4 Nuts 1 x 8-32 Cap Screw, 1/4" Long
Metric Kit Hex Keys, Ball Driver, and Screws
Metric Hex Keys: 1.3 mm, 2 mm, and 3 mm 1 x BD-5ML
Balldriver for M6 Screws
Metric Screws: 10 x M6 Cap Screw, 12 mm long 12 x M6 Cap Screw, 16 mm Long 4 x M6 Cap Screw, 20 mm Long
12 x M6 Washers 4 x M6 Nuts 1 x M4 Cap Screw, 6 mm Long
EDU-SPEB1 & EDU-SPEB1/M Chapter 4: Setup
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4.2. Component Assembly First, mount all of the lenses in the LMR1(/M) and FMP1(/M) mounts as specified below and screw each mount to a Ø12.7 mm post. Next, place each post into a PH3 (PH75/M) post holder and attach a BA1(/M) post holder base.
1. LB1676 and LB1471 lenses in LMR1(/M) mounts (Figure 1a). 2. ACL2520U condenser lenses in FMP1(/M) mounts (Figure 1b). 3. Attach each mount to a TR3 (TR75/M) post, place into a PH3 (PH75/M) post
holder, and attach a BA1(/M) base using a 1/2" long 1/4"-20 (12 mm long M6) cap screw.
Figure 1 : Ø1” Lenses in LMR1(/M) (a) and FMP1(/M) (b) Mounts, on Ø1/2” Posts
Next, mount the VA100(/M) slit and LEDMF led mount to posts in a similar fashion:
1. VA100(/M) adjustable slit on TR3 (TR75/M) post (Figure 2a) 2. LEDMF LED bracket on TR3 (TR75/M) post (Figure 2b) 3. Place each post in a PH3 (PH75/M) post holder. Attach a BA1(/M) base to the
slit, and a BA2(/M) base to the LED holder using 1/2" long 1/4"-20 (12 mm long M6) cap screws.
The LED mount also has interchangeable adapters for smaller LED sizes.
Next, mount the prism on the KM100PM(/M) prism mount and the grating in its CH1A mount:
1. GR25-1205 and GR23-0605 gratings each in a CH1A (Figure 3a) 2. PS858 Prism on KM100PM(/M) (Figure 3b) 3. Attach each mount to a TR3 (TR75/M) post, place into a PH3 (PH75/M) post
holder, and attach BA2(/M) bases using 1/2" long 1/4"-20 (12 mm long M6) cap screws.
a) b)
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Figure 2 : Adjustable Slit VA100(/M) (a) and LEDMF LED Mount (b) on Ø1/2” Posts
Figure 3 : Grating in CH1A Mount (a), and Prism in KM100PM(/M) Mount (b), both on Ø1/2”
Posts
b) a)
b) a)
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Mounting the KM100PM(/M) or the CH1A on a Post
Instead of a threaded hole for mounting, the KM100PM(/M) and the CH1A each contain a counterbored hole. To post mount these parts, first remove the setscrew from the post that you are using. Insert an 8-32 (M4) cap screw through the counterbored hole in the universal mount, and tighten it into the post on the other side of the hole.
4.2.1. LED Wiring The LED included with the kit can be powered using a simple battery or DC power supply. A resistor is also needed in the circuit in order to avoid damaging the LED. Wire the LED in series with the battery and resistor by soldering or using alligator clips. The ideal resistance, R, in ohms, may be calculated using the following formula, where I is the specified LED operating current, VL is the specified LED operating voltage, and Vs is the battery or power supply voltage. Use a resistor with the lowest value available that is still greater than the calculated resistance.
For example, using the LEDWE-15 LED included with the kit, a 4.5 V battery and a 68 resistor wired in series will produce a voltage drop of 3.2 V across the LED and a current of 20 mA, which will sufficiently power the LED.
4.3. Setup and Adjustment
4.3.1. Light Source Setup Take the two condenser lenses, the standard lens with focal length f = 50 mm, and the slit and assemble the components as shown in Figure 4, using 5/8" long 1/4"-20 (16 mm long M6) cap screws and M6 washers to attach components to the breadboard.. Next, position your light source at the end of the breadboard. The goal is to focus as much light as possible from the light source on the slit. Depending upon the form and the size of your light source, the standard 50 mm focal length lens may be omitted.
Place the first condenser lens directly behind the light source, the second at a distance of about 40 mm behind the first (curvature facing inward). The function of these lenses is to “catch” as much light intensity as possible. The standard lens with f = 50 mm should now be positioned at a distance of 50 – 60 mm behind this. It will then focus the light on the slit. Place it in the beam path after approximately an additional 50 mm (focal length of the
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lens). As the light sources used usually are not ideal point light sources, you often see a small image of the light source in this focus point (e.g. coil filament, LED-chip, Hg-tubes). This can be useful for focusing.
Figure 4 : Beam Path from Light Source to Slit
Next, focus the image of the slit on the grating. For this, place the second standard lens (f = 100mm) in the beam path, as shown in figure 5. The distance from the slit should be 10-15 cm. Insert the dispersive element (grating, prism) after the lens after an additional 10-15 cm.
Place the TPS5 laser safety screen on the breadboard as shown in figure 4. This will shield the viewing screen from stray light emitted by the light source.
4.3.2. Prism Spectrometer Setup When you place the prism into the beam path, ensure that you do not direct the beam through the matte side of the prism. Instead, this side of the prism should be facing between the black laser safety screen and the white viewing screen. Turn the prism until you see a sharp spectrum on the screen and make any necessary adjustments with the lenses and the distance of the screen. The slit, prism, lenses, and screen are shown in Figure 5, and the complete prism spectrometer setup is shown in Figure 6.
5-6 cm 4 cm 5-6 cm
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Figure 5 : Beam Path from Slit to Prism to Screen
To obtain an optimum image, change the slit width. The further the slit is opened, the brighter/more intense the image becomes, and the tighter it is closed, the sharper the image becomes.
10 - 15 cm 10 - 15 cm
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Figure 6 : Prism-Based Spectrometer Complete Beam Path
4.3.3. Grating Spectrometer Setup The grating-based spectrometer setup is the same up to the f = 100 mm lens (see section 4.3.1, above). You must now focus the light on the grating. The complete grating-based spectrometer setup is shown in Figure 7. The illustration shows the first order to the right of the zeroth order of the 600 lines/mm grating.
Place the screen so that you can observe the spectrum. Once again, make fine adjustments to the lenses or screen for a sharp image.
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Figure 7 : Grating-Based Spectrometer Complete Beam Path
Tip: Due to the sawtooth-like grating structure, the number of observable orders depends upon the direction the grating has been rotated in relation to the optical axis.
On one side of the zeroth order, you obtain a particularly intense image in the first order. This image is visible even with weak room lighting.
On the other side of the zeroth order, the spectra are less intense (similar to "normal" non-blazed gratings). In order to view this image, the room should be darkened. However, you can even observe the 5th order on this side with the grating with 600 lines/mm. Also note that the red/orange range of the 3rd order overlaps the blue/violet range of the 4th order.
Tip: If the grating or the screen is moved or rotated somewhat, the lens between the slit and the grating must also be adjusted accordingly. Move it back and forth somewhat in the beam path until a sharp image is obtained.
Tip: If you place a white sheet of paper on the screen (bleached), you can even observe UV lines (if present). This is due to the fact that the paper contains bleaches that fluoresce (absorb UV light and emit visible light) to make the paper look brighter under daylight.
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Chapter 5 Spectrometer Theory
5.1. Introduction A number of experiments can be conducted with this spectrometer kit. First, various types of light sources and spectra can be analyzed. Suitable light sources include:
Incandescent Lamps Compact Fluorescent (Energy Saving) Lamps LEDs Gas Discharge Tubes Including Mercury or Sodium Vapor Lamps
The most important parameters or objects of study of the spectrometer are:
Qualitative:
Relationship between slit width and spatial resolution. Relationship between slit width and intensity of the spectrum. Relationship between grating constant and spatial resolution. Observation of the differences between the diffraction orders.
Quantitative (listed here as an example):
Calculation of the wavelengths of spectral lines by means of the grating equation with the aid of a grating.
Calculation of the refractive index of the prism glass with the prism.
Many other applications are possible, which can also be interdisciplinary. An example of this is the examination of the absorption of chlorophyll. For this, one could first examine the spectrum of an incandescent lamp and then place a cuvette with dissolved chlorophyll in the beam path. As a result, one sees which color components are absorbed the most by the chlorophyll.
5.2. Wave Interference with Double Slits and Gratings
5.2.1. Double slit Consider a set of slits (double slit), as shown in Figure 8a and 8b. The dimensions of the slits should be smaller than the wavelength of the incoming light.
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Figure 8 : Double Slit Showing (a) Waves Emanating from the Two Point Sources and (b)
Path Length Difference Between the two Slits
Light hits the double slit in the form of a planar wavefront (Figure 8a). In accordance with Huygens' principle, each slit is then the origin of an elementary spherical wave, also called an elementary wave for short. These two elementary waves spread out behind the slit and overlap. Areas of constructive and destructive interference are created, which result in bright and dark areas when an image is viewed on a screen. We consider any point P behind the slits, which is so far removed that we can observe the wave trains emanating from the slits as parallel (Figure 8b). The path difference Δs between them is Δs = g sin. With the aid of geometrical optics, we can then easily see that we obtain constructive interference for integral multiples of the wavelength and destructive interference for half-integral multiples.
For maxima, the following must be true:
sin , 0,1,2,...ns g n n For minima, the following must be true:
1sin , 0,1,2,... 2n
s g n n
This is also easy to understand intuitively, because at points of maximum intensity, "wave peak meets wave peak" if the phase difference of the wave trains is one wavelength and "wave peak meets wave trough" if it is one half wavelength.
a)
g
∆s
P
P
b)
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5.2.2. Grating Interference
We can model a grating as a number of slits, N, as sketched in Figure 9.
Figure 9 : Path Length Differences Between Grating “Slits”
For the sake of clarity, we will refrain from a detailed, theoretical explanation of gratings, but can still make the following conclusions:
Intensity: The intensity I0 of the interference pattern becomes greater as more slits are illuminated: If the amplitudes of the individual wave trains overlap, the intensity is I = (NA)2, as the output amplitudes A0 of the electrical field vectors add up. (note that intensity results from the square of the field amplitudes).
Interference: As is the case with the double slit, the differences in pathways of the wave trains from the individual slits must also be an integral multiple of the wavelength of the incident light in the case of the grating in order to obtain constructive interference. For the maxima, the following grating equation is in effect:
sin , 0,1,2,...n n n
g
Here, g is the grating spacing, is the wavelength of the incident light, and n the diffraction order observed under the angle n. In conclusion, the spectral separation at the grating results from the diffraction by the slits.
∆s
g
n
2n
3n
4n
P
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From this correlation, it is immediately obvious that the angle n depends upon the wavelength of the incident light. If we examine light that is composed of many wavelengths, as is the case with our light sources to be examined, these wavelengths are spatially split, and we obtain a spectrum. These characteristics apply regardless of whether the grating works in transmission or reflection. In addition, it is apparent that larger wavelengths also result in a larger deflection angle (as opposed to a prism – here the behavior is reversed).
Resolution: The spatial resolution A of a spectrometer can be derived as follows:
A n N
Once again here, n is the diffraction order, Δ is the smallest observable wavelength difference, and N is the number of illuminated slits. In order to determine Δ, one can observe in the present setup, for example, whether known spectral lines (such as the orange lines in the mercury spectrum) can be perceived separately.
The formula above immediately reveals that the resolution increases with increasing diffraction order and increasing number of illuminated slits. In addition, one can demonstrate that the resolution increases as the slit width of the illustrated slit becomes smaller. In accordance with the grating equation:
sin , 0,1,2,...n n n
g
it becomes clear that the angle widening of the image increases with increasing fineness of the grating (meaning decreasing the grating spacing g) and the resolution is therefore improved. It is therefore interesting to compare gratings with various grating constants1.
5.3. Dispersing Prisms “Dispersion” in the context of a prism means that the angle of refraction of light is highly dependent on wavelength. This is the case in so-called dispersion prisms. Such prisms have an equilateral triangle as a cross-sectional area and consist of suitable glasses with high dispersion, e.g. crown glass. Light is directed at one side of the prism. It is refracted once upon entering the prism at the air/glass interface and finally once again upon exiting the glass/air interface.
1 In this kit, g = 1/(600 lines/mm) vs. g = 1/(1200 lines/mm)
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As the refractive index depends upon the light wavelength, Different wavelengths of light are refracted at different angles, and are thus spatially separated.
Figure 10 : Angle of Minimum Deviation in an Equilateral Prism
The angle of minimum deviation (see Figure 10) with incident angle and refractive angle is obtained if = . Here, the beam within the prism runs parallel to the base of the prism. With the aid of geometry, one can derive the following:
60 2 60 In this case, the law of refraction can be written as:
60sin 2
sin 30 n
Therefore, if one measures the minimal deflection angle, which can be sharply focused and thus determined well, one can determine the refractive index of the prism material at an observed wavelength (see sample exercise in Chapter 6.2). 2
Refraction in a Prism
The refractive index of the prism material depends upon the wavelength of the incident light. Since the deflection angle is ultimately determined by the refractive index, the various wavelengths can be separated spatially. This is a normal dispersion in the glass, meaning that the refractive index increases with reduced wavelength (blue light is refracted more than red). This is particularly interesting as the deflection in the grating behaves exactly in the opposite manner (smaller deflection angle for blue light). Figure
2 The supplied prism has an angle of minimum deviation of 47.9° at 633 nm. See the graph below for index of refraction vs. wavelength.
60°
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11 shows the index of refraction over the visible wavelengths for F2, the glass used to construct the prism.
Figure 11 : Index of Refraction vs. Wavelength for F2, the Glass Used in the PS868 Prism
Resolution with the Prism Spectrometer
The spatial resolution A of a prism is defined as
dnA b d
Here, b is the base length of the prism and dn d
is the relative dispersion.
For didactic purposes in the classroom, the most reasonable approach is certainly to estimate the possible resolution based only on the observation of certain spectral lines (e.g. orange lines in the mercury spectrum). You can also compare the resolution with that of the grating.
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Chapter 6 Teaching Tips and Experiments Due to its simplicity, the spectrometer kit makes it possible for students to build a spectrometer themselves. Here, the following qualitative exercises are possible:
Setup and adjustment of the spectrometer. Observation of several orders: for a grating with 600 lines/mm, up to 5 orders
(only in one direction due to the blazing angle) can be recognized. Observation of which quantities the resolution of the spectrometer depends
upon. For the grating spectrometer, two gratings are available for this purpose with different grating constants.
Grating/prism Differences: resolution, deflection angle (prism: greater deflection of short wavelengths, grating: situation is reversed)
Observation of ultraviolet spectral lines: Attach a white sheet of paper to the observation screen. The bleach fluoresces by absorbing UV light and emitting blue visible light, making ultraviolet spectral lines visible.
And, last but not least, analysis of the spectral makeup of various light sources.
It is also possible to conduct quantitative experiments, such as:
Determination of wavelengths from the deflection angles of the gratings with the aid of the grating equation (see exercise 1, section 6.1)
Determination of the refractive index of the prism material by determining the smallest deflection angle (see exercise 2, section 6.2)
In general, it is also interesting to discuss that the spectral analyses of the light for gratings and for prisms are based on different mechanisms: diffraction in the grating due to the grating structure and refraction in the prism due to the wavelength-dependent refractive index of the prism material.
6.1. Exercise 1: Wavelength Measurement of Three Lines in the Mercury Spectrum
In order to make the calculations as simple as possible, we set up the experiment so that we can use the simple grating equation
sin , 0,1,2,...n n n
g
This is the case if the light from the slit hits the grating perpendicularly. We therefore orient the grating perpendicularly to the optical axis – we can guarantee perpendicular incidence if we position the grating so that the zeroth order hits the slit. In addition, the observation screen should be positioned so that it is in line with the slit, so that the angle between the grating, slit, and screen is 90° (see Figure 12).
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Figure 12 : Measuring the Angle at which Light Leaves the Grating can be Used to Calculate
Wavelength
We want to use the wavelength based on the spectrum of the first order to the right of the zeroth order, as this is the most intense (this is in the nature of the blazed grating, see section 5.2.2). We use the grating with 1200 lines/mm.
Therefore, we already know n = 1 and g = 1/(1200 lines/mm). In order to determine the wavelength , we therefore still need the deflection angle , as shown in Figure 12.
We thus determine x and y as designated in Figure 12 and obtain:
arctan x y
.
The following results come from a simple determination of x and y with a ruler during a student experiment. The three most intense lines of the mercury spectrum were measured:
x (cm) y (cm) Exp (nm) Reference (nm)
24.2 25.0 580 577 (orange) 22.0 25.0 551 546 (green) 15.5 25.0 439 436 (blue/violet)
90°
y
x
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If one compares the values of the wavelengths determined in this manner with the literature values, the error rate is under 2%.
6.2. Exercise 2: Measuring the Index of Refraction of the Prism Using a Known Spectral Line
As shown above, we only need to measure the smallest deflection angle in the prism to determine refractive index.
In Figure 13, light hits the prism from the left and is refracted in the smallest deflection angle as shown in the image. We can very easily determine this angle by measuring the drawn distances x and y. The following equation applies:
arctan y x
Figure 13 : Measuring the Angle of Minimum Deviation in a Prism
Naturally, one can only roughly estimate the point that lies within the prism. But, the advantage of this method is that it is no longer necessary to determine the incident and refractive angles.
The setup shown in Figure 14 can be used to measure the angle of minimum deviation. When one turns the prism slightly in the beam, the position with the minimal deflection angle produces the most intense image. In order to obtain a sharp image, the position of the screen should also be moved back and forth somewhat until the optimum image is achieved. As the value of the refractive index of the prism glass is listed as 1.617 at 633 nm, we recommend measuring a red spectral line for ease of comparison. However, as a mercury vapor lamp is commonly available, we used an orange line of the mercury spectrum in the test example.3
3 Refer to Figure 11 for index of refraction data at other wavelengths.
y
x
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Figure 14 : Measuring the Angle of Minimum Deviation
The following example comes from a simple determination of x and y with a ruler during a student experiment. The results of 3 independent measurements are listed:
The distances x and y can usually not be determined more precisely than 0.5 cm in the student's experiment, which results in a systematic error of about 4%. In addition, there is a statistical error of several percentage points. Our result for the refractive index here is only subject to deviations of less than 2% and is therefore well within the margins for error, even though the method is relatively simple.
x (cm) y (cm) Exp (°) Reference (°) nExp @ 579 nm nReference @
633 nm 13.5 16.5 50.7 47.9 1.65 1.62 14.5 16.0 47.8 47.9 1.62 1.62 15.5 18.5 50.0 47.9 1.64 1.62
x
y
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Chapter 7 Regulatory As required by the WEEE (Waste Electrical and Electronic Equipment Directive) of the European Community and the corresponding national laws, Thorlabs offers all end users in the EC the possibility to return “end of life” units without incurring disposal charges.
This offer is valid for Thorlabs electrical and electronic equipment: Sold after August 13, 2005 Marked correspondingly with the crossed out “wheelie
bin” logo (see right) Sold to a company or institute within the EC Currently owned by a company or institute within the
EC Still complete, not disassembled and not contaminated
As the WEEE directive applies to self contained operational electrical and electronic products, this end of life take back service does not refer to other Thorlabs products, such as:
Pure OEM products, that means assemblies to be built into a unit by the user (e.g. OEM laser driver cards)
Components Mechanics and optics Left over parts of units disassembled by the user (PCB’s, housings etc.).
If you wish to return a Thorlabs unit for waste recovery, please contact Thorlabs or your nearest dealer for further information.
7.1. Waste Treatment is Your Own Responsibility If you do not return an “end of life” unit to Thorlabs, you must hand it to a company specialized in waste recovery. Do not dispose of the unit in a litter bin or at a public waste disposal site.
7.2. Ecological Background It is well known that WEEE pollutes the environment by releasing toxic products during decomposition. The aim of the European RoHS directive is to reduce the content of toxic substances in electronic products in the future.
The intent of the WEEE directive is to enforce the recycling of WEEE. A controlled recycling of end of life products will thereby avoid negative impacts on the environment.
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EDU-SPEB1 & EDU-SPEB1/M Chapter 8: Thorlabs Worldwide Contacts
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Chapter 8 Thorlabs Worldwide Contacts USA, Canada, and South America Thorlabs, Inc. 56 Sparta Avenue Newton, NJ 07860 USA Tel: 973-300-3000 Fax: 973-300-3600 www.thorlabs.com www.thorlabs.us (West Coast) Email: [email protected] Support: [email protected]
UK and Ireland Thorlabs Ltd. 1 Saint Thomas Place Ely CB7 4EX Great Britain Tel: +44 (0) 1353-654440 Fax: +44 (0)1353-654444 www.thorlabs.com Email: [email protected] Support: [email protected]
Europe Thorlabs GmbH Hans-Böckler-Str. 6 85221 Dachau / Munich Germany Tel: +49-(0)8131-5956-0 Fax: +49-(0)8131-5956-99 www.thorlabs.de Email: [email protected]
Scandinavia Thorlabs Sweden AB Bergfotsgatan 7 431 35 Mölndal Sweden Tel: +46-31-733-30-00 Fax: +46-31-703-40-45 www.thorlabs.com Email: [email protected]
France Thorlabs SAS 109, rue des Côtes 78600 Maisons-Laffitte France Tel: +33 (0) 970 444 844 Fax: +33 (0) 825 744 800 www.thorlabs.com Email: [email protected]
Brazil Thorlabs Vendas de Fotônicos Ltda. Rua Riachuelo, 171 São Carlos, SP 13560-110 Brazil Tel: +55-16-3413 7062 Fax: +55-16-3413 7064 www.thorlabs.com Email: [email protected]
Japan Thorlabs Japan, Inc. 3-6-3 Kitamachi, Nerima-ku, Tokyo 179-0081 Japan Tel: +81-3-6915-7701 Fax: +81-3-6915-7716 www.thorlabs.co.jp Email: [email protected]
China Thorlabs China Room A101, No. 100, Lane 2891 South Qilianshan Road Putuo District Shanghai China Tel: +86 (0) 21-60561122 Fax: +86 (0) 21-32513480 www.thorlabschina.cn Email: [email protected]
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