The Definitive Guide to a-BBO Crystal
The Definitive Guide to a-BBO Crystal
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The crystal axis is c. The Main ray is parallel for the path used to evaluate the tuning angle (θ), and that is optimized for the duration of stage matching. Conversion effectiveness is optimized for rays parallel to your Main ray and worse for rays at bigger angles (ψ) to the Main ray.
A2: Of course, prolonged publicity to humidity can degrade the optical effectiveness of BBO crystals. Humidity can cause h2o absorption to the crystal surface, which often can have an effect on its optical Attributes.
The flexibility of BBO crystals to change the frequency of sunshine has built them indispensable in laser engineering. They've got enabled the manufacture of a wide spectrum of sunshine hues, considerably beyond what exactly is specifically obtainable from offered laser resources.
The section matching angle is usually altered by rotating the crystal across the y axis. An adjustment that is typically inside of a couple levels can either improve the performance of the crystal in the setup or match An additional elementary frequency within the crystal's running assortment.
The energy density of your respective beam must be calculated with regard to J/cm2. The graph to the correct exhibits why expressing the LIDT as an energy density supplies the best metric for short pulse resources. On this routine, the LIDT presented as an energy density might be applied to any beam diameter; just one doesn't should compute an adjusted LIDT to adjust for modifications in place size.
In the situation of Style-I stage matching and β-BBO crystals, the elemental mild propagates as a unprecedented wave while in the crystal, while the next harmonic light-weight propagates as an ordinary wave.
Whilst the above mentioned method delivers a superb rule of thumb for LIDT values, make sure you Make contact with Tech Assistance Should your wavelength differs from the specified LIDT wavelength. If your electricity density is fewer than the altered LIDT in the optic, then the optic must do the job to your application.
It is often essential to emphasis the incident light during the crystal for SHG programs, because effective technology of 2nd harmonic light-weight demands significant peak intensities, such as 109 W/cm2. When working with femtosecond pulses with moderate energies in the nanojoule assortment, acquiring the demanded peak intensities can require compact focal spots.
This property sets it apart from linear optical materials that don’t change the frequency of light passing as a result of them. This type of distinguishing aspect varieties the inspiration for your plethora of purposes that BBO can serve.
The temporal stroll-off on the slower pulse with respect on the more rapidly might be a considerable fraction of the heartbeat duration. This can be illustrated in Figure 22.
The Uncooked resources, typically a mixture of barium carbonate and boric acid, are put in a very platinum crucible and heated until eventually they melt. The temperature is then steadily reduced, allowing for the BBO crystal to kind more than several months. The crystal is then extracted, Lower into the desired shape, and polished to obtain a significant-top quality optical surface.
The angular material in the resultant SHG pulse, or beam, from the dimension on the angular filter is lowered from a perfect circumstance. Within the perpendicular dimension, the SHG beam preserves the angular written content from the enter beam, because there’s no angular filter in that dimension. A diverging beam with asymmetric NA’s, i.e. while in the horizontal and vertical Proportions, leads to an elliptical beam.
The temporal walk-off is commonly thought of intense in the event the temporal click here lag exceeds the period of the basic pulse. Extreme walk-off can lead to temporal lag that irreparably increases the period with the output 2nd harmonic pulse.
The spectrally narrowed SHG pulse spectrum is said to get apodized, considering the fact that an effect of the fundamental pulse exceeding the utmost input bandwidth Restrict could be the removing of the best and lowest frequencies in the SHG pulse spectrum.