Recent content by a12b34c56

From what I could find so far light diffusers generate circular or elliptical beams but I did not find any references to rectangular beams.

Hello, I need to diffuse the beam from NICHIA NUBM36 to produce 20X20cm spot at 30-40 mm from the array. I was suggested two solutions: NUMB36->collimating lenses array->lens and rod or fly's eye. I don't think I need to collimate the beam more as the beam produced by NUBM36 is highly...

I think it is doable to get < 100 ns pulse if LD is soldered to the PCB that has a driver circuit so the capacitance is minimal. This is what they do with LIDARs and with RF applications. I believe they use pulsed 950nm Osram LDs that can do 75W in pulse but the pulse is shorter than 60 ns...

While it is a well known fact that LEDs can be overdriven when are run in pulsed mode generally it is not recommended to overdrive LDs. I found a number of papers which report that various CW LDs can reliably produce up to 30 times higher output in pulsed mode when driven with <10nc pulses. I...

I’ve got the spec. It does not say anything about pulse operations. I bought some red lasers that according to the spec can be run in both CW and pulse mode and they are rated for higher current in pulse mode. I wander if my IR LD is not designed for pulse operations at all. I did read Newport...

I believe 0.1% duty cycle is typical for pulsed LDs but they are run at much higher currents than CW LDs. Are you saying that the same rule is applied to CW lasers operated in pulsed mode? I thought I could get away with higher duty cycle as long as my pulse current does not exceed factory...

I have CW AlGaAs multi mode injection 1W IR LD. According to Chinese vendor it can operate in pulse mode. I’m running it with microsecond long pulses and < 1kHz frequency. Should I expect a significant decrease in its lifetime?

I understand the theory quite well as in my current line of work I involved with the design of fillers for TIM and EMI shielding. I started my career working in optoelectronics industry but I have not touched lasers for decades so I completely forgot that a human eye is one of the most sensitive...

Do you have any idea of D50 of Cu powder that you've used? I have tried different coatings: candle, black marker and graphite( which I just rubbed in) and got pretty much the same voltage readings for 100 &200mW 650nm and200Mw 830 nm pointers so I think low voltage output is indeed related...

I'm using cheap Chinese mutimiter so the calibration needs to be done periodically but I think even expensive one are not very stable. I'm mostly interested in red 630-660nm and IR 830-904 nm ranges. What are the dimensions of your cell?

I don't have a calibrated light source so I need somehow to calibrate it.

Hey farbe2, Thank you very much for very detailed and encouraging answer. 5% accuracy is very impressive! I’ve hoped to get at least 20% accuracy. Where on the cell did you glue the resistors near the perimeter of the cell? Do you use multi meter to read the voltage directly or op amp to...

It looks like quite a few people have built Peltier cell based laser power meters. I’ve seen different approaches to the heater for calibration and black paint. One approach to the heater is to attach a couple of resistors to the front side of the cell. The problem with this approach is that...

Hi, I want to drive a strip of 15 650 nm LDs (3V, 40ma) with 48V switching power supply. I intend to use constant current LED diver NSI45035JZ. https://www.onsemi.com/pub/Collateral/NSI45035JZ-D.PDF. I’ve got the driver but my scope has a pretty low bandwidth( 0- 200kHz) so I would not be able...