Bluefan
0
- Joined
- Aug 15, 2009
- Messages
- 1,443
- Points
- 48
I finally have the power meter of my dreams. It may not have a huge fancy color graphic display, the perfomance is the best I have seen so far:
A spectral flatness better than +/- 1% for 0.25um-2.0um and very flat beyond over the large 0.2um-20um it covers. Nearly all thermal detectors still vary 5% over such a wavelength range, but because the RkP-575 has a cavity absorber the light gets trapped. This means nearly 100% absorbtion and thus no need for calibration constants for a wavelength dependency.
10W max power with 100W/cm^2 maximum power density. Plenty for most lasers. A precision 1cm^2 aperture makes irradiance measurements easy, just directly read the power as W/cm^2. And 10W is plenty for most lasers out here.
And now the best part: it has a 100nW/sqrt(hz) noise level and a 10nW resolution! Even the most expensive high sensitivity thermal power meters I've seen have tens to hundreds of microwatts of noise and drift. I can measure lasers or even broadband light sources with only microwatts of power accurately and just as easy as lasers with watts of power on the same power meter.
I can now measure all the way from 10nw resolution on the lowest range to 10W on the highest range. The dynamic range from the noise level of 100nW to the full power of 10W is a factor 10^8, comparable to most photodiode based power meters. Typical thermal power meters like the ophir thermopiles or laserbee have a dynamic range of 10^3 to 10^4, that's 10,000 to 100,000 smaller.
And still the risetime is in milliseconds, comparable to fast thermal power meters, better than high sensitivty power meters (a few seconds) and far better than DIY peltier based power meters or laserbee's (a few more seconds to >10seconds).
Needless to say I'm very happy with this power meter, I can measure practically every CW laser except CO2 lasers and diode bars. It's a chopped pyroelectric power meter, so low reprate pulsed lasers won't register properly, but I don't have many of those.
I plan to do desctructive testing of laser safety eyewear. With the 10^8 dynamic range I can easily measure up to OD 7, no need for a photodiode based power meter for that. But with the 10W range I can determine how the eyewear keeps it's OD in case of a direct hit with a high power laser, a photodiode power meter would be damaged by such a laser. The power will be connected via GPIB to my computer for the logging of the power vs time.
Measuring my 473nm laser:
Measuring a 445nm laser I build for my university:
A spectral flatness better than +/- 1% for 0.25um-2.0um and very flat beyond over the large 0.2um-20um it covers. Nearly all thermal detectors still vary 5% over such a wavelength range, but because the RkP-575 has a cavity absorber the light gets trapped. This means nearly 100% absorbtion and thus no need for calibration constants for a wavelength dependency.
10W max power with 100W/cm^2 maximum power density. Plenty for most lasers. A precision 1cm^2 aperture makes irradiance measurements easy, just directly read the power as W/cm^2. And 10W is plenty for most lasers out here.
And now the best part: it has a 100nW/sqrt(hz) noise level and a 10nW resolution! Even the most expensive high sensitivity thermal power meters I've seen have tens to hundreds of microwatts of noise and drift. I can measure lasers or even broadband light sources with only microwatts of power accurately and just as easy as lasers with watts of power on the same power meter.
I can now measure all the way from 10nw resolution on the lowest range to 10W on the highest range. The dynamic range from the noise level of 100nW to the full power of 10W is a factor 10^8, comparable to most photodiode based power meters. Typical thermal power meters like the ophir thermopiles or laserbee have a dynamic range of 10^3 to 10^4, that's 10,000 to 100,000 smaller.
And still the risetime is in milliseconds, comparable to fast thermal power meters, better than high sensitivty power meters (a few seconds) and far better than DIY peltier based power meters or laserbee's (a few more seconds to >10seconds).
Needless to say I'm very happy with this power meter, I can measure practically every CW laser except CO2 lasers and diode bars. It's a chopped pyroelectric power meter, so low reprate pulsed lasers won't register properly, but I don't have many of those.
I plan to do desctructive testing of laser safety eyewear. With the 10^8 dynamic range I can easily measure up to OD 7, no need for a photodiode based power meter for that. But with the 10W range I can determine how the eyewear keeps it's OD in case of a direct hit with a high power laser, a photodiode power meter would be damaged by such a laser. The power will be connected via GPIB to my computer for the logging of the power vs time.
Measuring my 473nm laser:
Measuring a 445nm laser I build for my university:
