This assumes that scatter and absorption are insignificant but these smaller effects have a significant impact when very high reflectivity is required. Here you go. I was wondering whether there are also reflectance graphs available at different angles then 45 and 12, for example at 35 and 55 degrees AOI and normal incidence? The apparent finesse can then be reduced. opto-mechanical designer. This tutorial discusses recommended handling and cleaning methods in depth. Thanks a lot, After you have modified some inputs, click the "calc" button to recalculate the output. Unfortunately, this is highly dependent on factors such as absorption and thermal diffusivity, so there is no reliable method for determining when a high PRF laser will damage an optic due to thermal effects. Contact Tech Support for more information. The reflection loss at a single surface may seem small, but with multiple lenses, it becomes an unacceptable loss. how to clean fingerprint on the protected silver mirror? However, we may be able to offer these mirrors as part of a special production. I am not a photography buff, but had considered some sort of camera arrangement. The pulse length must now be compensated for. We have corrected this. PM. 我在反射镜参数中看到了“Parallelism”这个参数。不是很明白这个参数的意义。它是反映反射镜表面整体上凸起或凹下去的程度吗。是改变平行光的平行度的原因吗?请问平面镜对平行光的平行度的改变应该看哪个参数?. In order to illustrate the process of determining whether a given laser system will damage an optic, a number of example calculations of laser induced damage threshold are given below. Please note that we have a buffer built in between the specified damage thresholds online and the tests which we have done, which accommodates variation between batches. Response from Tor at Thorlabs to Nick: Thank you for your inquiry. You list these mirrors Laser Damage Threshold for pulsed lasers. All technical information is given on the specs table found in the Overview tab of this page. According to your specifications, damage breakdown of the silver coating appears at 3 J/cm2 at 1064 nm, 10 ns, 10 Hz, Ø1.000 mm. For a Gaussian output, these specifications result in a maximum energy density of 0.1 J/cm2. The shaded regions in the graphs denote the ranges over which we guarantee the specified reflectance. Tax Certificates, High reflectivity laser mirrors are critical components for beam steering, The industry standard method of measuring reflectivity does not tell the whole story, Reflectivity may seem simple but is actually a difficult value to measure, Cavity ring down spectroscopy (CRDS) measures total loss in order to determine reflectivity. One can also change the geometry to measure scattered light - if this is too large the mirror needs to be cleaned. Very interested in how this mirror effects polarization. Calculator for the Finesse. In our application just the breakdown because of average power is important. However, this false assumption does not consider scatter or absorption, leading to overly optimistic reflectivity values. Very often i have a broadband source and need to pick from the various metallic coatings and i find myself hopping around to piece the data together. Beam diameter is also important to know when comparing damage thresholds. Please note that we have a buffer built in between the specified damage thresholds online and the tests which we have done, which accommodates variation between batches. 78.46 Max/Min. When testing, take an image of the target directly, from *any* distance which is convenient; the inverse square law does not apply. Understanding and Specifying LIDT of Laser Components Read. A magnified, inverted image is located a distance of 32.0 cm from a concave mirror with a focal length of 12.0 cm. The silver coating allows little transmission over it's recommended operating range. TECHSPEC® 2µm Laser Mirrors feature >99.6% reflectivity and guaranteed laser damage thresholds of >10 J/cm2 at their design wavelengths for use with Holmium (2100nm) and Thulium (1940nm) doped laser systems. When comparing an LIDT specified for a pulsed laser to your laser, it is essential to know the following: LIDT in energy density vs. pulse length and spot size. Wavelength range is 450 - 2 um. The reflected laser light oscillates in the resonant cavity and a small amount of light is lost with each reflection. Diffuse reflectance is defined as the radiant flux that is in a scattering manner. Pulsed lasers with pulse lengths longer than 1 µs can be treated as CW lasers for LIDT discussions. This variation can certainly be an artifact of that, among other possibilities involving inconsistencies in the setup. Note that the apparent bandwidth of the resonances, observed e.g. Use 1 / f = 1 / do + 1 / di where f =15 cm and do = 45 cm, Then use hi / ho = - di / do where ho = 5 cm, do = 45 cm, and di = 30.0 cm. Note: this box searches only for keywords in the titles of encyclopedia articles. Mirror 2 could lead to system failure if it was believed to have a reflectivity of 99.99%. To be sure of consistency in target centering, you could employ a 'pointer' that easily swings out of the way when snapping pics. Isolation-19.14 dB. Sorry, we don't have an article for that keyword! The reflectivity of light from a surface depends upon the angle of incidence and upon the plane of polarization of the light. The measurement is absolute at the laser wavelength. We can produce individual custom plano, spherical, and aspheric mirrors as well as custom components for optical systems like our galvanometers. If a negative value is entered, the chemical formula is checked against a list of some common materials . I’ve tried measuring the reflectance spectrum with an ellipsometer and a reflectometer. This is to eliminate pixel-to-pixel variations due to noise and other artifacts if not calibrated. The general expression for reflectivity is derivable from Fresnel's Equations. Is it possible to get a rectangular mirror like PFSQ05-03-P01 on a thinner substrate while still maintaining high surface flatness?