Examine This Report on a-BBO Crystal
Examine This Report on a-BBO Crystal
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Frequent cleansing and correct storage can assist prolong the lifespan of BBO crystals. It’s also essential to prevent exposing the crystals to circumstances exterior their specified operating variety, as this could potentially cause long lasting problems.
The 266nm wavelength features specific interactions that other wavelengths can’t, making it indispensable for detecting and researching sure compounds.
Figure 22: The diagram at the highest shows two pulses with distinct center frequencies incident on a cloth. The group velocity delay involving the pulses whenever they enter the material is zero.
However, it’s essential to Be aware that although BBO crystals can deal with high electric power, they need to however be made use of in just their specified electricity vary to prevent possible injury and make sure exceptional functionality.
Any contamination can degrade the optical efficiency in the crystal and potentially induce harm less than substantial laser energy. When storing BBO crystals, they must be placed inside of a protective circumstance to stop Actual physical problems and mud accumulation.
As the next harmonic mild propagates, its Electrical power flows in a unique way than that of the fundamental light.
The spatial walk-off angle depends upon the dimensions with the beam plus the crystal length. Even though the angle can be sizeable, it is frequently smaller, ordinarily within the purchase of ten mrad, and may be neglected.
The angular content of a focused beam can be visualized by tracing rays with the lens towards the focal place. Every single ray drawn from your lens to the tightly targeted place (Figure 23) tends to make a different angle (ψ) With all the click here chief ray, and the variety of angles boosts While using the NA. As the range of angles increases past the reference NA filter (or angular domain apodization filter width), the phase-matching of your rays beyond the filter width diminishes hence decreasing the SHG conversion effectiveness of These rays.
When pulse lengths are in between 1 ns and 1 µs, laser-induced harm can happen either due to absorption or possibly a dielectric breakdown (hence, a person must Verify the two CW and pulsed LIDT). Absorption is both on account of an intrinsic residence with the optic or as a consequence of area irregularities; thus LIDT values are only legitimate for optics Assembly or exceeding the surface area top quality specifications given by a company.
A5: Indeed, BBO crystals have fantastic thermal balance and might maintain their Qualities at place temperature. This means that they are often Utilized in a variety of environments without requiring Unique temperature Handle.
As will be discussed underneath, there is a focusing numerical aperture (NA) limitation on the SHG section-matching procedure specifically analogous for the spectral stage matching limitation talked over inside the previous section (
This fine-tuning capability means that BBO crystals can cater to both of those generic and highly specialized demands with equal finesse.
A advisable guideline for concentrating femtosecond laser pulses into a nonlinear crystal is to take care of a Rayleigh assortment that's not less than several times lengthier compared to the duration from the SHG crystal. This minimizes the possibility of harming the crystal, as well as lessens the destructive outcomes of spatial section mismatch and spatial (Poynting vector) stroll-off.
The spectrally narrowed SHG pulse spectrum is claimed to generally be apodized, given that an result of the elemental pulse exceeding the most enter bandwidth Restrict will be the removal of the very best and cheapest frequencies with the SHG pulse spectrum.