A Review Of a-BBO Crystal
A Review Of a-BBO Crystal
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Figure 15 exhibits the orientation of γ inside a laboratory frame rotation of your crystal. In this instance circumstance, the nonlinear crystal is mounted within an RSP1 rotation mount in addition to an RP01 rotation phase. Variations in γ and θ modify the orientation on the optic axis, . In cases like this, changes in γ have already been utilized to align with the horizontal aircraft and on the list of principle regular axes vertically. For the vertically polarized enter beam, this orientation makes it possible for the rotation phase for use to regulate θ.
Having said that, in many instances, the difference in the fundamental and 2nd harmonic pulse velocities could cause just one pulse to substantially lag the opposite.
While this guideline provides a common pattern, It is far from a quantitative analysis of LIDT vs wavelength. In CW applications, For illustration, problems scales far more strongly with absorption in the coating and substrate, which doesn't automatically scale effectively with wavelength.
As Formerly said, pulsed lasers commonly induce a distinct variety of harm into the optic than CW lasers. Pulsed lasers generally never heat the optic enough to break it; alternatively, pulsed lasers develop robust electric powered fields effective at inducing dielectric breakdown in the material.
BBO crystals is often cleaned employing a soft cloth or air blower. For stubborn stains, a delicate detergent or isopropyl Alcoholic beverages can be utilized. It’s essential to avoid using abrasive components that may scratch the crystal’s surface area. When cleaning BBO crystals, it’s vital that you use a delicate, round motion to stop scratching the surface.
Thorlabs expresses LIDT for CW lasers as a linear electricity density measured in W/cm. On this routine, the LIDT presented as a linear ability density may be placed on any beam diameter; one particular does not should compute an adjusted LIDT to regulate for modifications in location sizing, as shown by the graph to the best. Normal linear electric power density could be calculated using the equation down below.
Even though the test final results are only representative of 1 coating run, Thorlabs specifies injury threshold values that account for coating variances.
The Bodily, chemical, optical, and thermal properties of the α -BBO are much like All those on the BBO crystals, even so the α -BBO won't show the nonlinear optical Qualities as a result of central symmetry of its crystal structure.
Since the refractive index isn't going to change linearly with frequency in dispersive crystals like β-BBO, it is impossible to optimally period match every frequency within the input pulse's spectral selection Using the corresponding second harmonic frequency from the created pulse.
Also, spectroscopy, a way that’s essential in analyzing and comprehending the Qualities of assorted substances, reaps the rewards of BBO’s capabilities. Spectroscopy relies over the interaction between mild and matter to derive insights a few compound’s composition, framework, together with other properties.
This more info calculation assumes a uniform beam depth profile. It's essential to now adjust this Electrical power density to account for hotspots or other nonuniform intensity profiles and around determine a utmost Electrical power density. For reference a Gaussian beam generally has a highest Power density which is two times that on the one/e2 beam.
When selecting an SHG crystal, the pulse length from the laser resource need to be taken into consideration. A mismatch between the length and crystal thickness will bring on SHG pulses more time in time and narrower in spectral articles than possible underneath ideal ailments.
A advised guideline for concentrating femtosecond laser pulses into a nonlinear crystal is to keep up a Rayleigh assortment that is definitely at the least several periods lengthier than the duration of the SHG crystal. This minimizes the prospect of harming the crystal, together with lowers the adverse outcomes of spatial phase mismatch and spatial (Poynting vector) stroll-off.
This informative article dives deep into the advantages and one of a kind Qualities of BBO crystal and its paramount relevance in efficient frequency doubling and harmonics generation at 266nm.