An Unbiased View of a-BBO Crystal
An Unbiased View of a-BBO Crystal
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The basic field now driving the sort-I SHG procedure could be the Eoγ element with the incident field. At γ = 90°, there could well be zero SHG output, For the reason that drive subject Eoγ = 0.
The team velocities of the fundamental and 2nd harmonic pulses are also distinctive, even when section-matched, plus the magnitude with the team velocity mismatch depends upon the crystal Homes as well as optical frequencies from the pulses.
The placement of the eco-friendly curve is dependent upon θ. In this instance, the angle θ has long been tuned to supply a refractive index for 515 nm light-weight that matches the refractive index for 1030 nm light. This tuning angle is therefore optimized for Type-I SHG section matching and a elementary-frequency input beam of 1030 nm.
On the other hand, it’s important to Take note that even though BBO crystals can manage higher power, they must however be utilized within just their specified energy selection to stop possible hurt and ensure exceptional overall performance.
The Strength density within your beam really should be calculated with regard to J/cm2. The graph to the appropriate reveals why expressing the LIDT being an Electrical power density provides the most effective metric for short pulse sources. In this particular routine, the LIDT presented being an Vitality density is usually applied to any beam diameter; one will not ought to compute an modified LIDT to regulate for alterations in location dimensions.
The effectiveness of the SHG system decreases considerably as the fundamental beam diverges from its concentration, Because the pulse energy is distributed across a bigger beam cross area.
Although the above mentioned process offers a good rule of thumb for LIDT values, please Make contact with Tech Help Should your wavelength is different from the specified LIDT wavelength. If your power density is lower than the altered LIDT of the optic, then the optic must perform to your application.
As illustrated in the following table, the shorter the crystal, the broader the reference pulse spectrum. The desk beneath assumes a basic center wavelength in the in the vicinity of-IR.
Now compare the most energy density to that which can be specified given that the LIDT with the optic. When the optic was analyzed more info at a wavelength in addition to your working wavelength, the damage threshold must be scaled properly [three].
However, there is not any 2nd order nonlinear result in alpha-BBO crystal mainly because of the centrosymmetry in its crystal framework and thus it's no use for next order nonlinear optical procedures. In its place, alpha-BBO is extensively employed for fabrication of polarizers, polarizing beam displacers, stage retarders, birefringent plates, and time delay compensators Specifically These for UV and superior electrical power lasers.
Both of those broad-bandwidth pulses and temporal walk-off cause a reduction from the conversion effectiveness, as well as worsen the optical high quality of the second harmonic pulses. The suitable crystal thickness needs to be picked out to attenuate the two consequences.
For beams with a high PRF the two the typical and peak powers needs to be in comparison to the equivalent CW electric power. Moreover, for very transparent resources, There exists minor to no fall from the LIDT with increasing PRF.
The temporal wander-off is frequently thought of serious in the event the temporal lag exceeds the duration of the elemental pulse. Extreme stroll-off can lead to temporal lag that irreparably raises the period on the output second harmonic pulse.
In frequency conversion, BBO crystals are accustomed to alter the color of laser light, enabling the creation of a variety of hues that aren't straight available from available laser sources. In electro-optic modulation, They're employed to regulate the depth, stage, polarization, or way of the laser beam.