I am designing light using several LEDs to create white light. Now I would like to measure how homogeneous my light is using some kind of device or measurement techniques. Can anyone suggest any device name which can be used to measure homogeneity of light?
Bipul, In the beam profiler, there are two types. One is slit scan type. But I think Parviz intends the other CCD type such as BC106N-VIS/M of Thorlabs, which is CCD Camera Beam Profiler to measure beam profile over 30 µm - 6.6 mm in diameter at visible wavelength, 350 - 1100 nm, in Metric. I know it is convenient in specific use such as to measure M^2 for laser Gaussian beam. My point is you can do better job on a versatile industrial CCD camera connected to PC in your application.
With a gonio-photometer you can look at the intensity distribution.
With a gonio-spectroradiometer you can also look at the spectral distribution of the light.
Modern high-level computerized photo camera from Canon or Nikon can be used to solve Your problem as for homogeneity of intensity so for right spectral distribution to realize the true white light.The same for Your task can be used devices based on camera for measurement intensity of laser emission from the correspondent companies...
The homegenuity of your white light can be measured as the standard deviation of imager signal over a lot of imager pixels illuminated. Up-to-date CCD/CMOS camera enables to measure it within error of 1~2%. Measurement error is mainly due to pixel-to-pixel sensitivity variation of CCD/CMOS imager, called fixed pattern noise (FPN). You can reduce FPN using pixel by pixel differnciating two frames; one is for your test field, the other is for ideally flat field.
Thank you very much Harry J. Wondergem for your suggestion. I have some misunderstanding using the gonio-spectroradiometer or goniophotometer, would you please clear that. First of all, as we have goniometer setup in our lab, it is huge and also time consuming because it takes measurement in all directions. My light setup in a booth, from the desk level it is around 1 meter high the light position. Currently I am using spectrophotometer to get the illumination data. Is there any other kind of device that easily can be used on the desk to measure the Homogeneity?
Thank you very much Mr. Eugene. So what are you proposing, taking photo (gray scale image) through camera and do some mathematical calculation to find out the homogeneity, also compare with any reference light to check the error rate. Did I understand right?
Parviz, a beam profiler is a good idea. One of them uses the same CCD imager which we use for speckle contrast measurement. See attached pdf. Problem I think around it is intended to measure Gaussian beam distribution but is not ideal for top hat beam display. CCD camera using the CCD imager is available from many vendors. You only connect the camera to PC through USB or GigaE. Then display on PC, measuremnet through ImageJ.
Beam Profiler sounds new to me and I have no idea how does this work, can you give me any idea @Parviz Parvin. Thank you very much
Bipul, In the beam profiler, there are two types. One is slit scan type. But I think Parviz intends the other CCD type such as BC106N-VIS/M of Thorlabs, which is CCD Camera Beam Profiler to measure beam profile over 30 µm - 6.6 mm in diameter at visible wavelength, 350 - 1100 nm, in Metric. I know it is convenient in specific use such as to measure M^2 for laser Gaussian beam. My point is you can do better job on a versatile industrial CCD camera connected to PC in your application.
Thank you very much Sir, you made the point clear to me. I am trying to implement the techniques in my lab. Have a good day.
Yes. You can use CCD camera to find qualitatively the beam profile, whereas the beam profiler utilizes some softwares to plot 3D intensity distribution of beam sross section determining the M2 factor too. The detector is calibrated over wide spectral range of 300- 1100 nm as well.
Multiplicative Lighting Correction by a digital color camera would be possible for your objective.
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