A few universities and observatory work in the near infrared spectrum, so it seems, and had manufactured or obtain filters in the J H K bands? I wonder where their source is?
What sensor are you going to use?
Silicon-based sensors will not work for J,H,K bands. Expensive and specialized non-silicon detectors. For example the Gemini Obs. has a camera that uses a 1k-1k InSb sensor with a selection of filters that cover 1 to 5 microns. As far as I know neither the sensors nor the filters are generally available and so would be very expensive if you can source something at all.
The other requirement is observing is best done from desert high altitude mountain sites.
Here is a write up on filters, atmosphere transmission, mirrors, optics, etc. All must be considered when designing and building a system. The higher the wavelength the harder it gets because the telescope and everything starts to glow the closer you get to thermal IR. Note this camera is using a HgCdTe-based detector.
JHK WIRCam filters - Canadian Astronomy Data Centre
Perhaps the best thing to do is write and submit a proposal for an existing observing system.
The director may have other ideas for you on how to proceed.
The sensor would be InGaAs.
Last night I emailed Andover corp that appear to offer a selection of IR band filters. Quote from their website
“ Andover Corporation has been producing custom J-band, H-band, K-band, L-band, M-band, and even N-band IR filters for years. Each band can be customized to fit your project.”
I will see if they reply.
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I’m sure you know… “custom” = $. Good luck!
If memory serves me correctly, the CHARA SILMARIL instrument, uses custom HK’ filters from Asahi Spectra. They had very specific requirements for filter transmission which are described in CHARA Technical Report 105.