Optical Lens Selection for 612nm Laser Source

[csocean]

Hi,

I'm trying to set up a lens system as follows:

- Laser source 612nm
- This passes through an apature to act as a spatial filter...
- then through non-reflective glass onto a crystal of diameter upto 150um
- the lens must then take the diffraction pattern from this crystal upto 50 degrees from the optical axis and focus onto a 7x9mm CCD

I have looked though a couple of catalouges and spoken to some people, but I keep having different terminology and jargon thown at me, and since my optics understanding is limited, I was hoping someone might guide me into how to make the right choice of lens. How do I minimise the abberations/distortions/other possible elements of error!

Thanks!

 

[csocean]

Ok, now I've been presented with the idea of using a reflecting ellipsoid... can anyone give me some pointers on how to set it up?

 

[astrokreng]

I can understand your confusion when it comes to selecting the right lens for your specific setup. It is important to consider certain factors such as the wavelength of your laser, the size and shape of your crystal, and the desired angle of diffraction when choosing a lens.

Firstly, the wavelength of your laser (612nm) is in the visible range and will require a lens with a high transmission in this range. You may want to consider using a multi-element lens instead of a single-element lens to minimize aberrations and distortions. Additionally, you may want to look for lenses with anti-reflective coatings to reduce unwanted reflections.

Secondly, the size and shape of your crystal will determine the focal length of the lens you need. A larger crystal will require a lens with a longer focal length to capture the diffraction pattern, while a smaller crystal may require a shorter focal length lens.

Lastly, the desired angle of diffraction (up to 50 degrees from the optical axis) will also play a role in lens selection. You may want to consider using a telecentric lens, which can maintain a constant magnification across a wide range of angles, to minimize distortions in the diffraction pattern.

In conclusion, to minimize aberrations, distortions, and other possible sources of error, you should consider using a multi-element lens with anti-reflective coatings, a focal length appropriate for your crystal size, and potentially a telecentric lens for your desired angle of diffraction. I suggest consulting with an optics expert or using lens simulation software to help guide you in your selection process.