The Single Best Strategy To Use For a-BBO Crystal
The Single Best Strategy To Use For a-BBO Crystal
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The superior problems threshold of BBO crystals is particularly vital in environments exactly where significant-depth lasers are the norm. Standard supplies may possibly falter, degrade, or maybe crack beneath this sort of intensities.
Beta Barium Borate (BBO) crystals have already been a topic of interest in the sphere of optics and photonics because of their exclusive Qualities. On this page, we intention to reply ten common questions on BBO crystals, offering a comprehensive knowledge of this interesting material.
The power of BBO crystals to change the frequency of sunshine has made them indispensable in laser technology. They have got enabled the manufacture of a wide spectrum of light colors, far over and above precisely what is immediately available from offered laser resources.
In place of the reference pulse electrical power spectrum comprising an apodization filter, while in the spatial area the filter will be in NA. The angular domain apodization filter even so, is only in one-dimension defined from the plane k and .
Figure 23: This diagram illustrates a beam's focal region inside of a uniaxial birefringent product. Straight lines, representing rays, are drawn throughout the center with the beam midsection. Given that the beam diverges through the beam midsection, the Electrical power from the beam is dispersed above a bigger cross sectional location.
Thorlabs expresses LIDT for CW lasers as a linear power density calculated in W/cm. Within this regime, the LIDT offered as being a linear ability density can be applied to any beam diameter; 1 would not should compute an adjusted LIDT to regulate for changes in location sizing, as shown from the graph to the best. Typical linear power density can be calculated utilizing the equation down below.
Figure 14 exhibits a departure from a great polarization orientation for Style-I SHG, exactly where the incident basic industry features a linear polarization but is rotated by a degree γ from your principal regular axis .
The angular information of a targeted beam might be visualized by tracing rays through the lens to the focal spot. Each and every ray drawn within the lens to some tightly centered place (Determine 23) will make a different angle (ψ) With all the Main ray, as well as choice of angles boosts Using the NA. Because the variety of angles boosts outside of the reference NA filter (or angular domain apodization filter width), the section-matching with the rays outside of the filter width diminishes hence cutting down the SHG conversion performance of Those people rays.
When pulse lengths are in between one ns and 1 µs, laser-induced hurt can take place either as a result of absorption or simply a dielectric breakdown (consequently, a consumer need to Test both of those CW and pulsed LIDT). Absorption is either due to an intrinsic residence from the optic or on account of surface area irregularities; thus LIDT values are only legitimate for optics meeting or exceeding the area top quality requirements supplied by a manufacturer.
Consequently, the second harmonic pulse spectrum, shown on the proper, incorporates a spectral width about the same as The perfect circumstance. Preferably, each frequency in the fundamental pulse spectrum might be concurrently stage matched.
Both of those wide-bandwidth pulses and temporal stroll-off result in a reduction while in the conversion performance, and also worsen the optical high-quality of the next harmonic pulses. The right crystal thickness ought to be picked out to minimize both of those effects.
The angular content with the resultant SHG pulse, or beam, during the dimension from the angular filter is reduced from an ideal situation. During the perpendicular dimension, the SHG beam preserves the angular written get more info content in the input beam, because there’s no angular filter in that dimension. A diverging beam with asymmetric NA’s, i.e. inside the horizontal and vertical dimensions, results in an elliptical beam.
When an enter pulse's spectral variety is equivalent to or narrower in comparison to the reference pulse, the generated 2nd harmonic pulse has a length that is certainly shorter by a factor of 1/√2 plus a spectral width that may be broader by a factor of √2.
This short article dives deep into the advantages and unique Homes of BBO crystal and its paramount relevance in efficient frequency doubling and harmonics generation at 266nm.