a-BBO Crystal Options
a-BBO Crystal Options
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The calculation earlier mentioned assumes a uniform beam depth profile. You have to now take into consideration hotspots within the beam or other non-uniform depth profiles and around work out a utmost electricity density.
The group velocities of the basic and next harmonic pulses are unique, even though phase-matched, plus the magnitude of the team velocity mismatch relies on the crystal properties plus the optical frequencies during the pulses.
There are 2 velocities that define the propagation of sunshine in optical media: the stage and team velocities. The stage velocity is definitely the pace on the copyright, the oscillation of the electric field, and the velocity that is matched amongst the fundamental and 2nd harmonic frequencies for period matching. The period velocity relative to your pace of sunshine in the vacuum is defined because of the index of refraction.
This effectiveness is vital, especially when a person considers the era of the 266nm wavelength, wherever even insignificant inefficiencies may result in substantial Strength losses.
The stage-matching capabilities of BBO crystals are worthy of special mention. From the intricate dance of photons, wherever conversion from 1 wavelength to a different is usually wanted, the period-matching offered by BBO makes sure that energy losses are small.
In the case of Style-I period matching and β-BBO crystals, the basic mild propagates as an extraordinary wave from the crystal, though the second harmonic mild propagates as a standard wave.
When the above mentioned treatment supplies a good general guideline for LIDT values, please Get in touch with Tech Guidance Should your wavelength is different from the required LIDT wavelength. In case your electric power density is fewer than the altered LIDT of your optic, then the optic should really perform for your software.
The angular content of a targeted beam might be visualized by tracing rays from the lens to the focal spot. Each and every ray drawn through the lens to some tightly targeted place (Figure 23) can make a unique angle (ψ) with the Main ray, along with the array of angles boosts Using the NA. Since the range of angles increases beyond the reference NA filter (or angular domain apodization filter width), the period-matching of the rays beyond the filter width diminishes thus reducing the SHG conversion effectiveness of All those rays.
BBO crystals must be handled with treatment to prevent scratching or harming their surfaces. They need to be saved in a dry, interesting position and retained faraway from direct daylight. Typical cleaning that has a delicate fabric or air blower is suggested to maintain their optical efficiency. When handling BBO crystals, it’s crucial that you use gloves to forestall oils through the pores and skin from contaminating the crystal surface area.
The group velocity would be the velocity of the heart beat, or more formally the envelope of the electrical subject. The team index similarly governs the pace with the envelope relative to the speed of light within a vacuum which is depending on the dispersion of the fabric.
Both broad-bandwidth pulses and temporal walk-off lead to a discount in the conversion efficiency, and also worsen the optical high-quality of the 2nd harmonic pulses. The right crystal thickness should be decided on to attenuate each results.
Beta Barium Borate (BBO) crystals have taken the globe of photonics by storm. Among the most remarkable components of these crystals is their groundbreaking part in 266nm generation.
The temporal wander-off is frequently thought of intense in the event the temporal lag exceeds the period of the basic pulse. Serious stroll-off can lead to temporal lag that irreparably improves the duration on the output second harmonic pulse.
The spectrally narrowed SHG pulse spectrum is said for being apodized, due to the fact an outcome of the fundamental pulse exceeding the maximum input bandwidth a-BBO Crystal limit may be the removal of the very best and cheapest frequencies through the SHG pulse spectrum.