The high destruction threshold of BBO crystals is particularly important in environments the place substantial-depth lasers would be the norm. Classic elements could falter, degrade, or perhaps break beneath these kinds of intensities.
Having said that, in many cases, the main difference in the fundamental and 2nd harmonic pulse velocities can result in a person pulse to noticeably lag the other.
Figure 22: The diagram at the top displays two pulses with different Heart frequencies incident on a cloth. The group velocity delay between the pulses every time they enter the material is zero.
This enhancement in clarity can result in early analysis and well timed intervention, probably conserving lives and bettering client results.
Figure 23: This diagram illustrates a beam's focal area in a very uniaxial birefringent material. Straight strains, representing rays, are drawn from the Middle of the beam waist. Since the beam diverges with the beam waistline, the Electricity while in the beam is distributed in excess of a larger cross sectional region.
Nonetheless, it’s crucial that you Observe that though BBO crystals can transmit UV mild, they ought to be taken care of with treatment when used in UV programs to prevent prospective damage to the crystal and guarantee safety.
The spatial walk-off angle will depend on the dimensions on the beam as well as the crystal size. Though the angle is often important, it is frequently smaller, typically over the get of 10 mrad, and will be neglected.
The angular content of the focused beam may be visualized by tracing rays within the lens on the focal location. Every ray drawn from the lens to some tightly concentrated location (Figure 23) can make a unique angle (ψ) With all the Main ray, along with the range of angles increases Together with the NA. Because the selection of angles will increase beyond the reference NA filter (or angular domain apodization filter width), the period-matching with the rays beyond the filter width diminishes consequently minimizing the SHG conversion effectiveness of All those rays.
Pumped with the fourth harmonic of the Nd:YAG laser (at 266nm), a tunable OPO with signal wavelength range among 422nm and click here 477nm is noticed by angle-tuning a type I BBO crystal. Pumped by a 1mJ, 80fs Dye laser at 615nm, the OPA with two BBO crystals yields a lot more than 50µJ (optimum a hundred thirtyµJ),
However, there isn't any 2nd order nonlinear influence in alpha-BBO crystal because of the centrosymmetry in its crystal construction and therefore it's no use for second get nonlinear optical processes. Rather, alpha-BBO is greatly employed for fabrication of polarizers, polarizing beam displacers, period retarders, birefringent plates, and time delay compensators Specially These for UV and substantial electrical power lasers.
This calculation assumes a uniform beam intensity profile. You have to now change this energy density to account for hotspots or other nonuniform intensity profiles and around compute a optimum Electrical power density. For reference a Gaussian beam commonly includes a highest Electricity density that may be 2 times that from the one/e2 beam.
This characteristic translates to diminished require for extensive thermal management methods, once again accentuating Price financial savings and program simplicity.
The 266nm era refers to the creation of ultraviolet light that has a wavelength of 266 nanometers.
This post dives deep into the benefits and unique Houses of BBO crystal and its paramount value in economical frequency doubling and harmonics generation at 266nm.