An Unbiased View of a-BBO Crystal
An Unbiased View of a-BBO Crystal
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The 2 frequencies' phase velocities are equal after they possess the similar refractive index. The refractive indices for these two frequencies are generally not equal, for the reason that all media except vacuum are dispersive. Which means a cloth's refractive index depends upon the light's frequency.
There are two velocities that determine the propagation of light in optical media: the phase and team velocities. The period velocity could be the speed of your provider, the oscillation of the electric industry, plus the velocity which is matched between the basic and next harmonic frequencies for section matching. The period velocity relative for the velocity of sunshine inside of a vacuum is outlined through the index of refraction.
A: A large injury threshold ensures the crystal can deal with far more power without the need of degrading, bringing about more time lifespan and dependable efficiency.
Any contamination can degrade the optical functionality of the crystal and probably trigger harm under higher laser electric power. When storing BBO crystals, they need to be positioned inside of a protective situation to prevent Bodily injury and dirt accumulation.
Thorlabs expresses LIDT for CW lasers as a linear power density measured in W/cm. In this regime, the LIDT presented for a linear ability density can be placed on any beam diameter; a person does not need to compute an altered LIDT to adjust for adjustments in location dimensions, as demonstrated from the graph to the ideal. Normal linear energy density can be calculated utilizing the equation beneath.
Physically, when the elemental spectrum is nicely throughout the reference pulse spectrum, the SHG pulse intensity profile could be the sq. of the basic depth profile, successfully truncating the period. This case is illustrated in Determine twenty.
The angular material of the centered beam can be visualized by tracing rays from the lens towards the focal spot. Just about every ray drawn in the lens to the tightly targeted place (Determine 23) tends to make a distinct angle (ψ) While using the Main ray, and also the variety of angles boosts Together with the NA. As being the number of angles improves outside of the reference NA filter (or angular domain apodization filter width), the stage-matching in the rays outside of the filter width diminishes as a result lowering the SHG conversion efficiency of People rays.
When pulse lengths are concerning one ns and 1 µs, laser-induced harm can happen either as a result of absorption or a dielectric breakdown (for that reason, a person need to Check out the two CW and pulsed LIDT). Absorption is possibly because of an intrinsic property in the optic or as a result of floor irregularities; As a result LIDT values are only legitimate for optics meeting or exceeding the floor high quality specifications supplied by a company.
The SHG light-weight is polarized while in the XZ plane and is orthogonal to both the Eo as well as the k-vector. Instead of decompose the polarization with the SHG light into Ex and Ez parts, the electric subject is usually called an extraordinary wave (E'e). The refractive index for this remarkable wave, n'e, improvements as being a operate of θ. n'e(θ) can be calculated utilizing the equation in Determine 13. The ellipse defining the remarkable index of refraction being a functionality of θ is actually a conic segment on the index ellipsoid.
A: The broad transparency vary gives versatility, allowing BBO crystals for use throughout a diverse selection of wavelengths and apps.
Future, the power/Power is either improved or diminished and also the optic is uncovered at 10 new destinations. This method is recurring until injury is observed. The problems threshold is then assigned to become the best power/Vitality which the optic can endure with out triggering problems. A histogram such as that under signifies the testing of one BB1-E02 mirror.
When an input pulse's spectral vary is equivalent get more info to or narrower compared to reference pulse, the generated second harmonic pulse provides a period that is shorter by an element of one/√two in addition to a spectral width which is broader by a factor of √two.
And finally, spectroscopy, the analyze of interactions involving issue and electromagnetic radiation, drastically Advantages within the 266nm generation. In spectroscopic applications, various wavelengths of sunshine interact in different ways with materials, delivering a spectrum that can be analyzed to ascertain the fabric’s Attributes or composition.