Thank you for your question! In contrast to a photodiode, PbSe sensors cannot convert CW light into an electrical signal. They behave like a passive resistor and cannot generate a photocurrent of their own. Changes in infrared radiation cause changes in the resistor value. By applying a bias voltage, this resistor change generates a voltage signal on a load resistance.
@@drmenghuang3342 Thanks for your question! This detector is AC coupled which means it ignores any DC signal (like what a CW laser would cause on a photodetector). You would have to use a chopper wheel, such as our MC2000B, and chop the CW light at a frequency matching the bandwidth spec of the PDA20H-EC (anywhere between 0.2Hz and 10kHz) for a signal to be picked up on the detector. If you are instead looking for an alternative detector option, please contact our Technical Support (techsupport@thorlabs.com) with more information on your specific wavelength and approximate power level.
Thank you for your questions! More information on photodetectors can be found here: www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3257&tabname=Photodiode_Tutorial. For any questions about specific applications, please contact techsupport@thorlabs.com.
Wow this is really great info- I am a relative noob looking to build a DIY photo detector to measure high speed particle flow
We’re happy you found it useful!
Hello your video is really good....please give information for bandwidth of photodetectors...basics of it...please
it's very nice video. My lab has a PDA20H-EC and my question is why this PD cannot measure DC light signal? Intensity modulated signal is OK.
Thank you for your question! In contrast to a photodiode, PbSe sensors cannot convert CW light into an electrical signal. They behave like a passive resistor and cannot generate a photocurrent of their own. Changes in infrared radiation cause changes in the resistor value. By applying a bias voltage, this resistor change generates a voltage signal on a load resistance.
@@thorlabs I got yourpoint. And do you have some suggestions if I have to detect a CW laser?
@@drmenghuang3342 Thanks for your question! This detector is AC coupled which means it ignores any DC signal (like what a CW laser would cause on a photodetector). You would have to use a chopper wheel, such as our MC2000B, and chop the CW light at a frequency matching the bandwidth spec of the PDA20H-EC (anywhere between 0.2Hz and 10kHz) for a signal to be picked up on the detector. If you are instead looking for an alternative detector option, please contact our Technical Support (techsupport@thorlabs.com) with more information on your specific wavelength and approximate power level.
@@thorlabs thanks
Good input.. My lab setup using the biased detector DET36A. Nothing coming out from the PD. Only DC signal appeared.No data received at all
Please give the reference for bandwidth of photodetector
Thank you for your questions! More information on photodetectors can be found here: www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3257&tabname=Photodiode_Tutorial. For any questions about specific applications, please contact techsupport@thorlabs.com.