The Definitive Guide to a-BBO Crystal
The Definitive Guide to a-BBO Crystal
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These crystals are unique thanks to their capability to change the frequency of light passing via them, a property that is highly popular in numerous fields for instance laser technological innovation and quantum physics. The flexibility of BBO crystals will make them an important part in several Highly developed optical units.
However, in many situations, the primary difference in the basic and second harmonic pulse velocities could cause a person pulse to significantly lag one other.
Although this general guideline provides a common development, It's not at all a quantitative Assessment of LIDT vs wavelength. In CW apps, For example, injury scales much more strongly with absorption while in the coating and substrate, which would not necessarily scale nicely with wavelength.
As previously mentioned, pulsed lasers ordinarily induce a special variety of injury to the optic than CW lasers. Pulsed lasers typically tend not to heat the optic ample to wreck it; alternatively, pulsed lasers develop strong electrical fields able to inducing dielectric breakdown in the fabric.
The period-matching capabilities of BBO crystals have earned Unique mention. While in the intricate dance of photons, wherever conversion from a single wavelength to another is often wished-for, the period-matching provided by BBO makes sure that Power losses are minimum.
Thorlabs expresses LIDT for CW lasers as a linear electrical power density measured in W/cm. In this particular routine, the LIDT given like a linear power density is often placed on any beam diameter; just one doesn't should compute an modified LIDT to adjust for changes in place dimension, as shown by the graph to the appropriate. Common linear electric power density is often calculated using the equation beneath.
Bodily, when the basic spectrum is effectively within the reference pulse spectrum, the SHG pulse intensity profile will be the sq. of the basic intensity profile, proficiently truncating the period. This case is illustrated in Determine 20.
The get more info angular content material of a concentrated beam is often visualized by tracing rays in the lens to your focal location. Each ray drawn from your lens to some tightly concentrated spot (Figure 23) makes a special angle (ψ) While using the Main ray, and also the number of angles raises with the NA. As being the number of angles increases outside of the reference NA filter (or angular domain apodization filter width), the section-matching from the rays outside of the filter width diminishes thus lowering the SHG conversion efficiency of People rays.
This property sets it apart from linear optical materials that don’t alter the frequency of light passing through them. Such a distinguishing feature forms the foundation for a plethora of applications that BBO can provide.
With good care and dealing with, BBO crystals can very last for many years. Even so, their lifespan is usually shortened by elements for instance superior temperature, humidity, and physical hurt. BBO crystals are robust and durable, but Like every optical part, they will degrade after some time Otherwise effectively cared for.
As will probably be talked over down below, There exists a focusing numerical aperture (NA) limitation into the SHG period-matching method precisely analogous into the spectral stage matching limitation talked about in the past segment (
For beams by using a large PRF each the standard and peak powers must be compared to the equal CW electricity. In addition, for really transparent materials, You can find small to no fall inside the LIDT with increasing PRF.
The temporal stroll-off is commonly regarded critical once the temporal lag exceeds the length of the fundamental pulse. Serious wander-off can lead to temporal lag that irreparably boosts the length of the output next harmonic pulse.
BBO’s versatility really shines when one considers the breadth of its programs. It’s not just confined to 1 area of interest of photonics but stretches throughout multiple domains. Consider frequency doubling, As an illustration. In this method, photons While using the same frequency combine within the crystal to produce new photons with double the frequency of the first.