The BBO Crystal Diaries
The BBO Crystal Diaries
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Equally broad-bandwidth pulses and temporal walk-off result in a reduction in the conversion efficiency, and worsen the optical high quality of the 2nd harmonic pulses. The suitable crystal thickness must be picked out to minimize the two consequences.
BBO crystals are developed using the flux strategy, a process that consists of melting Uncooked supplies at high temperatures. The molten materials is then bit by bit cooled to variety a crystal. This method needs precise Charge of temperature and cooling amount to ensure the crystal’s top quality and integrity.
A1: Certainly, BBO crystals Have a very superior hurt threshold, building them appropriate for substantial-electrical power laser programs. Their potential to withstand superior laser intensities without having struggling from optical harm tends to make them a wonderful choice for frequency conversion in substantial-ability lasers.
Borates including LBO and BBO also perform very well in broadly tunable optical parametric oscillators and optical parametric chirped-pulse amplification.
, the angle involving the light's propagation path along with the crystal's optic axis can be tuned so that the refractive index of a selected frequency (ω) in the fundamental enter pulse particularly equals the refractive index of twice the input frequency (2ω). It is actually common to enhance section matching disorders for the frequency at approximately the middle of the pulse's bandwidth.
The group velocity will be the pace of the pulse, or maybe more formally the envelope of the electric subject. The team index similarly governs the velocity in the envelope relative to the speed of sunshine in a vacuum and is particularly dependent on the dispersion of the material.
When an optic is broken by a steady wave (CW) laser, it is frequently mainly because of the melting from the surface on account of absorbing the laser's energy or damage to the optical coating (antireflection) [1]. Pulsed lasers with pulse lengths lengthier than 1 µs could be treated as CW lasers for LIDT conversations.
the chemical durability; e.g., some crystal products are hygroscopic, Many others go through chemical improvements when heated here in a very vacuum chamber for software of the dielectric coating
Beam diameter is additionally important to know when comparing problems thresholds. When the LIDT, when expressed in units of J/cm², scales independently of place dimension; significant beam measurements usually tend to illuminate a larger quantity of defects which may lead to increased variances within the LIDT [four].
To forestall this, BBO crystals really should be saved within a dry surroundings and effectively sealed when not in use. Furthermore, any cleaning system really should be followed by thorough drying to eliminate any residual dampness.
Dust and stains on crystal surfaces could potentially cause scattering/loss of light and may even react with mild to wreck optical surfaces at a superior incident laser electricity.
They also have a large harm threshold, permitting them to take care of significant-electrical power laser beams devoid of degradation. These unique Attributes make BBO crystals a flexible Instrument in various optical apps.
As a result, the second harmonic pulse spectrum, demonstrated on the correct, has a spectral width somewhere around similar to The perfect circumstance. Ideally, each individual frequency in the basic pulse spectrum could well be concurrently section matched.
The duration of the SHG crystal considerably impacts the spectral width of your reference pulse, or alternatively the bandwidth in the SHG filter.