BBO, Z-Cut, 4x4x20mm, AR coating and Cr+Au electroded for EO applications

Features:

• High repetition rate
• High peak power damage resistance
• Low absorption
• UV transmission
• Low acoustic noise

BBO crystals exhibit significant advantages over other materials in terms of laser power handling abilities, temperature stability, and substantial freedom from piezoelectric ringing. Because it relies on the electro-optical effect, switching time - aided by the low capacitance of the Electro-Optical Q Switch is very fast, therefore it is an splendid choice for high repetition rate lasers up to 1MHz , and all-solid-state short-cavity Q-switched laser using BBO electro-optic Q-switch can generate high-energy laser with a pulse width of less than 4ns, which is the preferred light source for electro-optic internal engraving machines. Without water cooling, the BBO electro-optical Q switch can be turned off and withstand up to 150W intracavity oscillation optical power (laser output power up to 50W). In addition BBO crystals has a wide transparency range of 200nm to 1650nm, which allows it to be used in diverse applications from UV to NIR spectrum. 

Hangzhou Shalom EO offers BBO crystals used in the pockels cells with high precision polishing, AR coating and Cr-Au electrodes, stocked crystals of standard specifications is ready for selecting, and the customized special crystals is also available upon customer's request. Besides we also offer BBO crystals for nonlinear applications.

Features of BBO crystal：

• Ultra-thin crystals can be used for ultra-fast (<10 fs) applications
• Wide phase matching range of various second-order nonlinear interactions in almost the entire transparent range
• The highest nonlinearity among all UV nonlinear crystals
• High laser induced damage threshold (LIDT)
• Wide transmittance range from 188 nm to 5.2μm (appropriate transparency @3μm-5.2μm, tens of μm thick crystal)
• Extremely low capacitance (1< pF) will permit high repetition rate switching with rise times on the order of 100 ps or less
• High damage threshold capable of withstanding high peak power intensities of samller beam size and therefore suitable for compact design ( However, small crystal aperture leads to diffraction losses and hence might increase the insertion losses.)
• Not prone to piezo-electric ringing
• Low absorption and associated laser-induced thermal birefringence
• High extinction ratio

Fig.1        Qualitative comparison of acoustic ringing in BBO and LiNbO3 

The intensity transmitted through the LiNbO3 Pockels cell varies greatly due to piezoelectric effects, whereas the light transmitted through the BBO Pockels cell

                                                                                         follows the decay of the applied high voltage pulse with no evident acoustic ringing

Applications:

1. High repetition rate DPSS Q-switches
2. High repetition rate regenerative amplifier control
3. Cavity dumping and Beam chopper
4. Low dispersion suitable for short pulse regenerative amplifiers

Application Notes:

Calculation of Quarter-wave Voltage

The voltage required to produce a retardance of π radians is called the halfwave voltage or simply Vπ. For an optical input linearly polarized 45o applying a halfwave voltage rotates the polarization by 90o. When the output wave is passed through a linear the resultant can be rapidly modulated from maximum intensity to minimum intensity by rapidly changing the voltage applied to the crystal from 0 volts to Vπ.

The halfwave voltage of BBO is dependent on the optical wavelength and is given by:

Where   λ=optical wavelength 
         d=electrode spacing 
         L=optical path length 
         r22=electro-optic coefficients 
no=ordinary indices of refraction

EO Q-Switch 1/4Wave Voltage Vs wavelength (4x4x20mm) 
1/4 Wave Voltage @1030nm : Vπ/2 =3388V