Coupling lasers to a widefield microscope?

Hardware
8

Dear Hazen and μforum,

Thank you for your guidance. I’ve designed a laser coupling system for our widefield microscope and would appreciate your feedback.

System Overview:

  • Source: Fiber-coupled lasers (488nm/25mW, 561nm/200mW, 640nm/500mW) via a common single-mode polarization maintaining FC/APC fiber (Mean Field Diameter: 4.6μm @ 630nm)
  • Collimator: 89mm focal length → 10mm beam diameter (1/e²)
  • Focusing lens: 200mm focal length → 10μm diameter spot at back focal plane
  • Objective: Nikon 100× objective → 174μm diameter illumination field

Mechanical Design: The collimator connects to the microscope’s back port via four precision rods. The focusing lens slides along these rods for alignment (see image).

image
image961×410 56.9 KB

Questions:

  1. Does this optical design look correct for epi-illumination?
  2. Will the four-rod mounting provide reliable alignment stability?

Thank you for any insights you can share.

Warmly,
Yossi