What Does BBO Crystal Mean?
What Does BBO Crystal Mean?
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A: Certainly, BBO crystals show remarkable thermal steadiness, creating them suited to purposes with different temperatures.
In lots of situations, a nonlinear crystal utilized for nonlinear frequency conversion has an incredibly lengthy lifetime, that's extended than that of The complete laser method. The crystal product is essentially not modified in the course of Procedure. On the other hand, a diminished crystal life time can manifest less than various instances:
Both have a comparatively low injury threshold, but will not should be operated at large intensities due to their high nonlinearity. They've an inclination for photorefractive effects, that happen to be detrimental for frequency conversion, but are employed for, e.g., holographic information storage in Fe-doped LiNbO3 crystals. The tendency for “photorefractive hurt�?is dependent strongly on the material composition; e.g. it could be minimized by means of MgO doping and by making use of a stoichiometric composition.
The fundamental subject now driving the kind-I SHG method may be the Eoγ component of your incident field. At γ = 90°, there can be zero SHG output, Considering that the generate field Eoγ = 0.
Broad openness variety: BBO crystals have a large openness array from 189 nm to 3500 nm, covering ultraviolet, noticeable, and in the vicinity of-infrared regions. This enables BBO crystals to be used for varied laser sources with different wavelengths.
These kinds of resilience ensures that its nonlinear Qualities are not easily compromised, making it a favourite in environments in which regularity and reliability are paramount.
The next harmonic frequency wave is produced as a rare wave, which can be polarized orthogonal to the fundamental-frequency standard wave.
The length of the crystal is a vital parameter to contemplate when optimizing the SHG method for your parameters of particular input pulses. Absent period-matching and temporal stroll-off effects, the SHG output increases exponentially with crystal duration. The objective when finding an SHG crystal is always to balance the crystal size with the restrictions based on the fundamental pulse. Reducing the crystal thickness cuts down consequences linked to both of those phase-matching bandwidth constraints and temporal walk-off, which happen to be directly related.
Physically, when the fundamental spectrum is properly within the reference pulse spectrum, the SHG pulse intensity profile could be the sq. of the elemental depth profile, effectively truncating the length. This case is illustrated in Figure 20.
Little acceptance angle: BBO crystals have a little acceptance angle that limits the enter light-weight beam’s light-weight beam divergence and top rated mode excellent for successful regularity conversion.
We use Numerical Aperture (NA) to describe the extent of this angular articles. Ideally, the basic laser gentle can be collimated all over the crystal, considering the fact that collimated gentle resembles a bunch of rays aligned to the identical course using an NA of zero.
The spectrally narrowed SHG pulse spectrum is said to generally be apodized, considering that an impact of the elemental pulse exceeding the most enter bandwidth Restrict would be more info the removal of the best and cheapest frequencies from your SHG pulse spectrum.
Third harmonic era (THG): We use THG to evaluate our pieces�?nonlinear conversion efficiency and period-matching angle for your given enter wavelength. We Make certain that our products satisfy the specs for THG purposes.
Because the refractive index won't vary linearly with frequency in dispersive crystals like β-BBO, it truly is impossible to optimally phase match each individual frequency inside the enter pulse's spectral array with the corresponding 2nd harmonic frequency from the created pulse.