Is it possible for a photodetector to determine the wavelength of light incident on it without accompanying Optics?

Submitted by Sin-Silver t3_10xrx53 in askscience

To to best of my understandings, photodetectors rely on the accompanying optics to select the wavelength of light incident on the detector, with the detector only determining the quantity of light hitting it.

For example filters in in a digital camera, or diffusion gratings in a spectrophotometer.

Are there any designs or principles by which a photodetector alone could provide information not just about the quantity of light hitting it, but the wavelength as well?

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mfb- t1_j7ycwvt wrote

Microbolometers measure the temperature change when radiation hits them, with very sensitive devices this can be used to measure the energy of individual photons - even in the infrared, higher energies (visible light, UV, ...) are easier than that.

Various x-ray and gamma detectors routinely measure the photon energy, or equivalently the wavelength.

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hatsune_aru t1_j82wvxr wrote

the bandgap of a photodiode determines the minimum energy of a photon that can trigger conduction, so you could use that to your advantage, but it won't be band-selective unless you forgo single photon detection.

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