About a-BBO Crystal
About a-BBO Crystal
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Figure fifteen shows the orientation of γ inside of a laboratory frame rotation in the crystal. In this example situation, the nonlinear crystal is mounted in an RSP1 rotation mount in addition to an RP01 rotation stage. Changes in γ and θ alter the orientation from the optic axis, . In cases like this, adjustments in γ are already accustomed to align With all the horizontal airplane and among the list of principle normal axes vertically. For the vertically polarized input beam, this orientation permits the rotation stage for use to adjust θ.
As well as their use in laser frequency conversion, BBO crystals have discovered purposes in electro-optic modulation and quantum optics experiments.
Determine 22: The diagram at the very best exhibits two pulses with various Middle frequencies incident on a cloth. The team velocity delay among the pulses whenever they enter the fabric is zero.
The stage matching angle is usually altered by rotating the crystal around the y axis. An adjustment that is typically inside of a few degrees can possibly enhance the overall performance from the crystal from the set up or match A further basic frequency in the crystal's functioning array.
Various things can influence the overall performance of BBO crystals. These involve temperature, humidity, and the standard of the incident mild. Proper managing and storage will help keep the crystal’s performance. Temperature can impact the stage-matching circumstances of BBO crystals, which in turn impacts their performance in frequency conversion purposes.
Thorlabs expresses LIDT for CW lasers being a linear electricity density calculated in W/cm. With this routine, the LIDT presented as being a linear energy density may be placed on any beam diameter; a person isn't going to ought to compute an modified LIDT to adjust for alterations in place dimensions, as shown with the graph to the correct. Regular linear energy density can be calculated utilizing the equation below.
In some instances, the mismatch is often smaller. For instance, every time a β-BBO crystal is utilized to frequency double 1550 nm click here light and provide 775 nm gentle, the team velocity mismatch is only a few femtoseconds for every millimeter.
Instead of decompose the SHG polarization into factors Ex and Ez, the light is often referred to as a rare wave (E'e) having a refractive index, n'e. During the diagram on the right, n'e, which will depend on θ, is indicated with the intersection from the conic section illustrated with the red ellipse Along with the XZ plane.
When pulse lengths are among one ns and one µs, laser-induced damage can happen either as a result of absorption or maybe a dielectric breakdown (hence, a person should Look at both CW and pulsed LIDT). Absorption is both as a result of an intrinsic property in the optic or resulting from surface area irregularities; thus LIDT values are only valid for optics Assembly or exceeding the floor high-quality specs specified by a maker.
The team velocity will be the pace of the heartbeat, or more formally the envelope of the electric discipline. The team index similarly governs the pace of your envelope relative to the speed of light in the vacuum and it is dependent on the dispersion of the material.
The basic supply is definitely the dye laser radiation pumped by the second harmonic of a Q-switched Nd: YAG laser. A stroll-off compensated configuration Together with the BBO crystal pair has enabled us to understand this type of significant conversion performance from the conversation.
The angular written content in the resultant SHG pulse, or beam, in the dimension of your angular filter is diminished from an ideal situation. During the perpendicular dimension, the SHG beam preserves the angular material with the input beam, considering that there’s no angular filter in that dimension. A diverging beam with asymmetric NA’s, i.e. in the horizontal and vertical dimensions, brings about an elliptical beam.
The temporal stroll-off is usually regarded as critical if the temporal lag exceeds the duration of the basic pulse. Significant walk-off can lead to temporal lag that irreparably improves the length in the output 2nd harmonic pulse.
On top of that, the structural and compositional characteristics of BBO give it with impressive thermal balance and resistance towards environmental difficulties.