Photodetector Definition and 18 Threads

I am calculating Responsivity of a pn junction photodiode (a.k.a the target) by irradiating radiation from LED sources. For this purpose, i have two LEDs, one UV and another green LED. Note that LEDs are placed close to the target.UV LED : Manufacturer has given total radiant power to be 20mW...

I am new to photodetectors. I know there are usually two concepts of bandwidths of photodetectors, i.e the spectral and electrical. What I do not understand is the electrical bandwidth. The electrical bandwidth is used to calculate the shot noise of a photodetector. However, the papers usually...

Hi, I'm studying p-i-n photodiode (PD) at the moment and understand that the photodiode's response will depend on the frequency of the light signal going into it. I am struggling however to understand the concept of bandwidth, and why is it that the photocurrent at the PD decreases with higher...

If I understand the phenomenon correctly; whenever we capture an image using a telescope, because the light that's emitted from a distance object acts like a wave, we notice a diffraction pattern in our image. Now, in the double slit experiment (I didn't create the image, excuse the "slot"...

Homework Statement As the title says, I'm trying to calculate the fundamental noise limit for an ideal photodetector, by specifically looking at the rate of incidence of annihilation of photons (and subsequent excitation of conducting electrons) on the detection surface. Since I'm looking for...

Hello! I am trying an interferometry experiment using the Michelson Morley experiment. I managed to obtain the interference pattern on a screen, but I want to use an photodetector and I am not sure what should I obtain. As I know, the oscilloscope shows the intensity of the light, so if I modify...

Problem Statement: my aim is to digitalize a 10ns narrow pulse coming from a photo diode with current ranging from 10nA-70mA, as its impossible to cover this dynamic range of >60dB using a single TIA i have an option of separating it to two channels as below using two diodes ofcourse Lowest...

Here's the thing: I'm a god-fearing humble man like yourselves, but I know jack about electrical engineering, yet I've found myself in a rather peculiar situation. In particular, I'm supposed to perform electrical engineering. So, we're supposed to design a model of a theoretical city, using...

If we use 2 lasers with selectable light intensities as input, with each level of intensity corresponding to decimal number. Like level 0 intensity - decimal 0 (MIN) level 1 intensity - decimal 1 level 2 intensity - decimal 2 ... level 9 intensity - decimal 9 (MAX) and directly shine both of...

Hello I just want to ask why do we bias the photodetector before starting any setup? Thank you

Hi, I would like to know how a detectors bandwidth can be measured? for example, if there is any relation with the produced current or what? I can't understand bandwidth concept. Thank you.

Is it possible to use interband transition to design mid-infrared photodetector? I want to design mid-infrared photodetector based on interband transition. I could not find any article that use interband transition for mid-infrared photodetector.

I'm trying to design a fiber optic sensor to sense vibration via intensity modulation. I'm new in this field and i don't know whether I can use a PIN photodetector for low frequency or not... what's the bandwidth of a PIN Photodetector? Does it mean its responsivity is limited in low frequency...

I was wondering if anybody could help me understand my measurements. I was interested in measuring the photo current and voltage of a red LED placed in room light and sun light. I measured the voltage across the LED and the current through in both conditions. In the room measurement, I am...

hello, I am currently working on a simple school project to make a sensor circuit. i need the circuit to include a photodetector (either photodiode, phototransistor or LDR) to sense and measure the intensity of a typical laser beam (from a cheap laser pointer), the main aim is to get a different...

I have a lay question that needs answering please. If a photodetector can display a single 'white dot blip' where a single photon has struck it, how can this be explained without requiring a physical size of the incident photon? Side Questions 1) Does a photon of higher energy leave a...

How would one set up a circuit where a photodetector closes a switch in a circuit once it detects light?

Help! is a photo detector the same as photosensor? can they be specifically for infrared light? and what does point source mean?