Everything about BBO Crystal
Everything about BBO Crystal
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Crystals which happen to be non-critically section-matched in the crystal oven may possibly exhibit difficulties if the crystal temperature is modified way too fast or far too generally. Specifically, anti-reflection coatings may very well be harmed as a result of various thermal growth coefficients of your included products.
The problem that occurs when working with ultrashort pulses for 2nd harmonic technology (SHG) is that shorter pulses have more substantial bandwidths, but the ideal stage-matched problem can be realized For less than an individual essential wavelength at a time. On account of this, the caliber of the period match can be drastically even worse in the direction of the spectral edges of wide-bandwidth pulses.
We lessened our boule into lesser goods As outlined by customer technical specs using a ruby blade, or twine observed device. After that, polish these parts employing ruby powder or slurry on cast iron or copper plates.
Note that even when the nominal intensity is down below the nominal problems threshold, there might be challenges because of fluctuations in the beam ability or nearby intensity (e.g., if a beam profile has “very hot spots�?, or resulting from isolated defects inside a crystal, that happen to be far more delicate as opposed to frequent crystal material.
For beams using a substantial PRF both of those the typical and peak powers should be when compared with the equivalent CW ability. Moreover, for really transparent elements, There is certainly click here minor to no fall while in the LIDT with rising PRF.
Numerous different phase-matching methods can be employed to equalize the refractive indices of the elemental and 2nd harmonic light-weight. One particular approach, which works by using linearly polarized light-weight as well as the distinction between the regular and remarkable refractive indices, is Kind-I important period matching. This is the prevalent technique for damaging uniaxial crystals wherein no > ne.
A advised guideline for focusing femtosecond laser pulses into a nonlinear crystal is to take care of a Rayleigh selection that is definitely no less than numerous times more time than the size from the SHG crystal. This minimizes the chance of harmful the crystal, and also lessens the destructive effects of spatial stage mismatch and spatial (Poynting vector) wander-off.
Cleaning BBO crystals is a fragile system that needs treatment to stop harmful the crystal’s area. A gentle fabric or lens tissue moistened using a moderate solvent, like isopropyl alcohol, can be utilized to gently wipe the surface on the crystal.
The superior harm threshold of BBO crystals is especially essential in environments wherever high-depth lasers are definitely the norm. Regular products may well falter, degrade, and even split under such intensities.
Small acceptance angle: BBO crystals have a little acceptance angle that boundaries the enter gentle beam’s mild beam divergence and top rated method high-quality for powerful regularity conversion.
Dust and stains on crystal surfaces could potentially cause scattering/reduction of sunshine and may even respond with light to break optical surfaces in a higher incident laser electric power.
BBO nonlinear crystal is a detrimental uniaxial crystal. It provides section matching for different next-get interactions Practically over its whole transparency range. This transparency ranges from 185 nm to 3.three µm, as inferred from transmittance measurements making use of crystal samples of some mm thickness.
When an input pulse's spectral variety is equal to or narrower as opposed to reference pulse, the produced 2nd harmonic pulse provides a period that is certainly shorter by a factor of one/√two in addition to a spectral width that is broader by an element of √two.
Massive angular walk-off BBO crystals have a major angular walk-off that triggers spatial splitting between several polarization parts of sunshine when circulating by using a BBO crystal.