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β-BBO Crystal—a greatly applied nonlinear crystal for frequency conversion in the ultraviolet, seen and in close proximity to-infrared
There's two velocities that outline the propagation of sunshine in optical media: the stage and team velocities. The stage velocity would be the speed on the copyright, the oscillation of the electrical field, plus the velocity that is definitely matched in between the fundamental and next harmonic frequencies for stage matching. The section velocity relative for the speed of light in a vacuum is defined via the index of refraction.
Nonetheless, to completely employ the prospective of BBO crystals, it is actually important to comprehend their Qualities and how to tackle and retail store them effectively. These crystals require mindful managing to stop harm to their surfaces and should be stored in the dry, interesting spot to maintain their optical effectiveness.
From a ray-design viewpoint, the propagation route defines the orientation from the central (chief) ray in Determine 23. The SHG system is impacted with the selection of angles above which incident light-weight propagates, for the reason that mild that's not parallel to the chief ray has decreased stage-matching relative towards the chief ray.
). This spatial focusing constraint about the SHG process will usually bring about the crystal size always being lower than the Rayleigh choice of the enter concentrated pulse.
While the above technique supplies an excellent general guideline for LIDT values, be sure to Get in touch with Tech Guidance if your wavelength is different from the required LIDT wavelength. In case your power density is a lot less than the adjusted LIDT on the optic, then the optic really should perform in your software.
Some companies' SHG crystals, which include Thorlabs', give near-stage-matched disorders for Commonly incident input light-weight for a specified elementary frequency. These brands polish the faces from the SHG crystals such the angle involving the Typically incident light as well as optic axis is the stage-matched angle for the required frequency.
For the reason that refractive index doesn't change linearly with frequency in dispersive crystals like β-BBO, it can be not possible to optimally phase match just about every frequency inside the enter pulse's spectral range with the corresponding 2nd harmonic frequency in the produced pulse.
With correct treatment and managing, BBO crystals can previous for many years. Having said that, their lifespan might be shortened by factors for example superior temperature, humidity, and physical injury. BBO crystals are robust and durable, but Like all optical part, they are able to degrade after some time Otherwise correctly cared for.
Every single side of BBO, from its atomic construction to its wide application spectrum, underscores its pivotal position in modern science and know-how.
When evaluating an LIDT specified for just a pulsed laser on your laser, it is vital to be aware of the subsequent:
The duration of the crystal is an important parameter to take into consideration when optimizing the SHG process for the parameters of specific enter pulses. Absent period-matching and temporal wander-off consequences, the SHG output increases exponentially with crystal duration. The intention when choosing an SHG crystal is usually to harmony the crystal duration with the restrictions determined by the fundamental pulse. Decreasing the get more info crystal thickness lowers outcomes connected to both phase-matching bandwidth restrictions and temporal walk-off, which happen to be straight connected.
On top of that, the structural and compositional attributes of BBO supply it with outstanding thermal stability and resistance versus environmental troubles.