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This process is repeated until damage is observed. Next, the power/energy is either increased or decreased and the optic is exposed at 10 new locations. The number of locations that are damaged at a particular power/energy level is recorded. After exposure, the optic is examined by a microscope (~100X magnification) for any visible damage. The optic is exposed in 10 locations to this laser beam for 30 seconds (CW) or for a number of pulses (pulse repetition frequency specified). Thorlabs' LIDT testing is done in compliance with ISO/DIS 11254 and ISO 21254 specifications.įirst, a low-power/energy beam is directed to the optic under test. For more information on cleaning optics, please see our Optics Cleaning tutorial.
#Cut off wavelength free
Because dust or other particles on the surface of an optic can cause damage at lower thresholds, we recommend keeping surfaces clean and free of debris. Note that the guideline presented here assumes room temperature operation and optics in new condition (i.e., within scratch-dig spec, surface free of contamination, etc.). Pulsed lasers, on the other hand, often strip electrons from the lattice structure of an optic before causing thermal damage. Continuous wave (CW) lasers typically cause damage from thermal effects (absorption either in the coating or in the substrate). The LIDT for an optic greatly depends on the type of laser you are using. When choosing optics, it is important to understand the Laser Induced Damage Threshold (LIDT) of the optics being used. The following is a general overview of how laser induced damage thresholds are measured and how the values may be utilized in determining the appropriateness of an optic for a given application.
![cut off wavelength cut off wavelength](https://www.thorlabs.com/images/xlarge/7697-xl.jpg)
Excellent Suppression in Rejection Region (OD > 5).
![cut off wavelength cut off wavelength](https://l450v.alamy.com/450v/rpxk1c/airborne-radar-airplanes-guided-missiles-538-antennas-and-rf-components-fig-10-12-cross-section-of-rectangular-waveguide-showing-width-a-which-governs-cutoff-wavelength-there-is-a-definite-cutoff-wavelength-at-wavelengths-greater-than-cutoff-for-a-particular-mode-the-transmission-line-will-not-propagate-energy-in-that-mode-the-lowest-order-mode-or-dominant-7node-is-that-waveguide-mode-having-the-longest-cutoff-wavelength-or-lowest-cutoff-frequency-in-rectangular-waveguide-this-is-the-tio-mode-fig-10-llc-which-has-a-cut-off-wave-length-xc-of-la-fig-10-12-the-tao-mode-rpxk1c.jpg)
25.0 mm Outer Diameter (Ø21.1 mm Clear Aperture).