optics

Here we consider system with two scanning mirrors to scan a laser beam in the focal plane of a microscope objective. We relay the scanners to the microscope pupil via a telescope consisting of a small first lens of focal length f1 = 75 mm and a larger lens of focal length f2 = 200 mm separated by the sum of their focal lengths. Ideally the second lens functions like a tube lens in that its back focal point is at the pupil of the objective and a real image is formed at the point where the rays cross in the figure.

Ideally, we would place the scanning mirrors at the front focal plane of the first lens so they would be conjugate to the microscope pupil. However, the two mirrors cannot occupy the same location so we place them 10 mm before and after this location. We will move the mirrors so that the laser beam moves through ±5 deg at the mirrors.

a. Where are the scanner images (as seen through the two relay lenses) relative to the pupil?

b. What is the angle of the scan after the two lenses (i.e. at these images).

c. As the beam is scanned, it moves away from the center of the pupil.

How far does it move? Draw pictures to show this.

d. If the focal length of the objective is 10 mm what is the full field of

view of the scanned image in millimeters?