The linked project uses a 4000px wide image sensor and the second example in the article is a solar spectrum like what you want. It's not as sharp, but it's remarkably good given that the diffraction grating was a fragment of a DVD and the opening was a 3D printed slit.
940-1240nm isn't "uv to ir" like you described, though. That's just pure deep infrared. You'd have to test to see if the camera's image sensor was sensitive in those regions with any filters removed, but I doubt you'd get much signal in the deep IR region. Good sensitivity that far outside of the visible range requires a specialized sensor. Some security cameras designed for "invisible IR" will have such a sensor inside, so you could start by looking there.
Photons of different wavelength are absorbed and converted at different depth in silicon sensors. Blue photons mostly convert at the surface, while red go much deeper into the sensor. The pixel electronics of a regular cmos image sensor however will only collect the resulting electrons in a certain region at the surface. If an electron is generated somewhere else, it will recombine and be 'lost', not contributing to the signal.
Depending on the sensor, at 1000nm only <10% of the photons will result in electrons that are captured by the pixel electronics. The sensor does not give you any signal any more.
Why? Silicon has a band gap of 1.12eV - photons with lower energy will not interact. This corresponds to ~1100nm - you will need sensors with different materials
- an array detector, which is pricey.
- a single detector such as a photodiode behind a second slit. a detector such as these https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=12... With a moving(rotating) grating, so that the wavelengths can be reached by moving the grating.
The latter is quite common in lab spectrometers.
Off the shelf you're looking at around $8k for a spectrometer from Ocean Optics. Just point the fibre at sun on a white PTFE plate outside (teflon has pretty uniform reflectivity) and it should work. You generally need an InGaAs sensor to go beyond 1000 nm with any appreciable sensitivity. Silicon is still sensitive to around 1200, but performance drops significantly. The solar image from NASA is only in the visible anyway, but as I mentioned in another post the simplest way to do this is to use a high lines per mm grating (e.g. 1200) and rotate it so you capture multiple spectra in shorter ranges.
[0] http://www.astrosurf.com/buil/spectrographs.html
[1] https://www.oceaninsight.com/products/spectrometers/general-...
I don't know how long most commercial imaging sensors typically go, but you'd also have to do some work to remove the IR filter that's typically added by the manufacturer. There are a number of tutorials for this.
We’d stick a standard CCD (like in any DSLR) behind them, and voila! You have a spectrometer! This would also give you a good optical path, for focusing light.
You’d still need to calibrate the driver, but that’s just paperwork.
I'm probably missing something obvious, but could it be done by using a larger number of inexpensive setups?
There's no reason that each camera has to be focused on the same part of the grating, right? 4x cameras, point each at a different region and stitch it in software.
It's more complicated to use multiple cameras on one grating because you'd need far more light shielding.
Like something that can plug into something as universal as an audio jack on a phone, reflecting the laser back into its built in camera. I know there was some options out there that were cloud-based but I want one simply lets us interpret the samples and their readings ourselves with lab device quality output.
DIY stuff like this is ultra cool but it's like miniaturize-able for sure, and something you can run with open source software.
I know it's around the corner, I've read about it. It's like the next killer feature for new cell phones already. [1] Making it open source so some corporations who are doing cloudy things with your spectrometer data is definitely an international research security imperative.
Fascinating teardown on one of these things at Ben Krasnow's channel https://www.youtube.com/watch?v=KdfHVcU8U7U .
https://www.hackster.io/news/les-wright-s-diy-raspberry-pi-s...
Does it just have a much larger spectrum?
