You’re considering whether it would be possible - and perhaps quite elegant - to use an XY‑scanner to raster‑scan the end of an optical fiber across a prism, disperse the light, and then capture the resulting spectrum with a CCD line sensor.

With that setup, each pixel on the line sensor would effectively record the full spectral content of the light at that scanned position, all in a single acquisition.

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tomtom1337 an hour ago | parent | next [-]

You could probably use just an X-scanner, and instead of a CCD line sensor, use a regular 2D image sensor if you used a "1 pixel wide" slit aperture to crop the image perpendicularly to the direction that the prism disperses the light. So instead of a single pixel being dispersed, you disperse a line.

You would reduce the time required by the root of the number of pixels you want (assuming a square image).

(This is what we do in momentum-resolved electron energy loss spectroscopy. In that situation we have electromagnetic lenses that focus the electrons that have been dispersed, so we don't have as bad a chromatic aberration problem as the other response mentions).

I would love to see e.g. a butterfly image with a slider that I could drag to choose the wavelength shown!!

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asdff an hour ago | parent | prev [-]

A problem for multispectral imagery (even within visible rgb), is that the wavelengths of light are different so the lens cannot be in focus for all spectrum at once. I have tested this out with a few of my slr lenses. If you have blue channel perfectly in focus, red isn't just a little out of focus, it is actually noticeably way out.

	▲	tomtom1337 an hour ago \| parent \| next [-]
		This is called chromatic aberration, for those who are intrigued. Given that regular phone cameras have sensors that detect RGB, I wonder if one could notice improved image sharpness if one had three camera lenses (and used single-color sensors) next to one another laterally, with a color filter for R, G and B for each one respectively. So that the camera could focus perfectly for each wavelength.
	▲	lytfyre an hour ago \| parent \| prev \| next [-]
		there are lenses out there designed for apochromatic performance across the UV-Vis-IR band, but they tend to be really pricey. The Coastal Optical 60mm is a frequently cited one. UV in particular is challenging, because glass that works well in the visible light range can be quite poorly translucent in UV. Quartz is better, but drives up the cost a lot, and comes with other tradeoffs.
	▲	dheera an hour ago \| parent \| prev [-]
		I've had this problem as well, but it's just due to optical properties of the lens and extremely consistent from image to image, so you can calibrate and correct for it as long as you focus each wavelength and collect data separately.