a-BBO Crystal Things To Know Before You Buy
a-BBO Crystal Things To Know Before You Buy
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The higher problems threshold of BBO crystals is especially significant in environments wherever high-depth lasers will be the norm. Standard materials might falter, degrade, or simply crack beneath such intensities.
Regretably, it might be quite challenging to match the LIDT specification of the optic to your laser. You will discover many regimes during which a pulsed laser can harm an optic which is predicated within the laser's pulse length. The highlighted columns during the table underneath define the relevant pulse lengths for our specified LIDT values.
While this general guideline supplies a basic development, It's not a quantitative analysis of LIDT vs wavelength. In CW purposes, As an example, damage scales a lot more strongly with absorption from the coating and substrate, which would not always scale very well with wavelength.
When a single of such β-BBO Crystals is mounted from the RSP1 mount, the crystal might be centered above the 8-32 (M4) hole in the mount's foundation without the will need for spacers.
The energy density of your beam needs to be calculated when it comes to J/cm2. The graph to the ideal displays why expressing the LIDT being an Power density provides the most beneficial metric for short pulse resources. In this particular regime, the LIDT offered as an Electrical power density can be applied to any beam diameter; 1 isn't going to need to compute an adjusted LIDT to regulate for variations in spot dimensions.
). This spatial focusing constraint over the SHG approach will generally result in the crystal duration generally being below the Rayleigh variety of the enter centered pulse.
The next harmonic frequency wave is produced as a unprecedented wave, which is polarized orthogonal to the fundamental-frequency ordinary wave.
Some makers' SHG crystals, such as Thorlabs', provide in close proximity to-period-matched disorders for Commonly incident enter gentle for just a specified elementary frequency. These suppliers polish the faces of your SHG crystals these which the angle amongst the Ordinarily incident light-weight along with the optic axis is definitely the section-matched angle for the required frequency.
For example, look at a fundamental pulse propagating above a specified crystal thickness. When the temporal walk-off is larger when compared to the period of the fundamental pulse, this pulse will also have a spectral bandwidth that drastically exceeds the spectral width of the reference pulse. A common rule for limiting the detrimental results related to the two Actual physical effects is to decide on a crystal thickness that limits the basic and next harmonic temporal wander-off to not more than the duration of the fundamental pulse.
A5: Sure, BBO crystals have exceptional thermal steadiness and will preserve their Homes at place temperature. This means that they can be read more used in an array of environments devoid of demanding Distinctive temperature Management.
This calculation assumes a uniform beam depth profile. You have to now alter this Electricity density to account for hotspots or other nonuniform depth profiles and roughly compute a utmost energy density. For reference a Gaussian beam generally provides a most Power density which is twice that of your 1/e2 beam.
When choosing an SHG crystal, the heartbeat length with the laser resource must be taken into consideration. A mismatch concerning the length and crystal thickness will result in SHG pulses for a longer period in time and narrower in spectral content material than probable beneath great conditions.
The temporal walk-off is often regarded as extreme once the temporal lag exceeds the duration of the fundamental pulse. Serious walk-off can lead to temporal lag that irreparably raises the length in the output 2nd harmonic pulse.
The problem that occurs when working with ultrashort pulses for next harmonic technology (SHG) is usually that shorter pulses have larger bandwidths, but the ideal phase-matched situation is often achieved for only just one fundamental wavelength at a time. Because of this, the quality of the phase match can be noticeably even worse toward the spectral edges of wide-bandwidth pulses.