Source prototype relay lenses

@Stephanie Lu

Recommendation:

Thor Labs AC127-019-C
1. Pros: Manufacturer seems reliable, price is less expensive that other options, 12.7 mm diameter and 19 mm focal length seem okay, lens is available immediately, the lens is 100% an achromatic doublet
2. Cons: Would be better if focal length was smaller (see option 2), AR coating range only covers 1050-1700 nm instead of 900-1700 nm
Opto Axis
1. Pros: Has the smallest focal length (15 mm) I’ve found yet with a 12 mm diameter
2. Cons: Not sure if it’s an achromatic doublet or if it’s just an achromatic lens but the diagram looks like a doublet? Not sure what wavelength range it covers, but the substrate listed is commonly used for SWIR lenses. Not sure how to actually buy the lens or what the price is.
(Honourable Mention - not in the database) Firebird Optics Achromatic Doublet Lens
1. Pros: 12.5 mm diameter with 18 mm focal length, BBAR coating (750-1550 nm), starting from $134.00 which seems reasonable
2. Cons: Unavailable

Overall thoughts:

Seems hard to find something with a diameter greater than 12 mm and a focal length less than ~18 mm
A lot of websites don’t seem to explicitly state the wavelength range, but might tell you the coating or the substrates (some of which seem like common ones for SWIR - BBAR coating and N-LAK22/N-SF6)
Not sure if my recommendation is necessarily the “best” option, but I think it’s the best one that I have so far and ThorLabs seems more trustworthy + provides a lot of information about their products

Diameter → 12 mm - 100 mm (closer to 12 mm is better)

Focal length → 0 mm - 25 mm (smaller is better)