This discussion centers on the efficiency of mirrors, particularly in laser applications, and the limitations of reflectivity across different wavelengths. Laser mirrors, specifically dielectric multilayer mirrors, can achieve reflectivity up to 99.99% for targeted wavelengths, while conventional metal mirrors like gold can reflect 99.0% at 10um. The conversation highlights the specificity of mirror design for optimal performance in narrow wavelength ranges, emphasizing that no mirror can reflect all wavelengths at 99.999% efficiency.
PREREQUISITESOptical engineers, physicists, and anyone involved in laser technology or mirror design will benefit from this discussion.
intervoxel said:How can a mirror reflect 99,999% of incident light? Or in other words what makes a photon exiting a laser cavity so directional?
In fact, I never found a really convincing answer. Thank you.
Nice answer, ZapperZ. Let's suppose now one single photon with the correct wave length to get maximum reflection. What happens to the properties of the photon to have higher probability of detection in a very closed angle cone in the direction of reflection?ZapperZ said:Your question is vague. No mirror can reflect ALL wavelengths at 99.999% efficiency. The regular mirror that you and I are used to may appear to be a good reflector of visible light, but put that in a UV-VIS spectrometer, and you'd be surprised at reflectivity spectrum, even in the visible range. And forget about UV, because such a mirror is hopeless.
Mirrors in laser cavity has been specifically selected so that it has the highest reflectivity in a very narrow range of wavelengths. So it has been finely tuned to work under a very narrow parameter.
Zz.
intervoxel said:Nice answer, ZapperZ. Let's suppose now one single photon with the correct wave length to get maximum reflection. What happens to the properties of the photon to have higher probability of detection in a very closed angle cone in the direction of reflection?