At this sort of a specific wavelength, the light possesses special Homes that happen to be a must have to particular Sophisticated purposes. Permit’s delve further into the necessity of this specific mild output.
From the intricate tapestry of photonics, the 266nm generation, backed through the prowess of BBO, emerges like a thread of paramount significance.
In an effort to use the specified CW injury threshold of an optic, it's important to find out the subsequent:
As previously stated, pulsed lasers ordinarily induce a unique sort of damage towards the optic than CW lasers. Pulsed lasers usually don't warmth the optic sufficient to wreck it; alternatively, pulsed lasers develop sturdy electric powered fields able to inducing dielectric breakdown in the fabric.
From the ray-design point of view, the propagation route defines the orientation with the central (Main) ray in Figure 23. The SHG procedure is afflicted with the array of angles over which incident light-weight propagates, simply because gentle that's not parallel to your Main ray has minimized phase-matching relative towards the chief ray.
As the next harmonic mild propagates, its energy flows in a unique way than that of the elemental light-weight.
Bodily, when the fundamental spectrum is perfectly inside the reference pulse spectrum, the SHG pulse depth profile may be the sq. of the basic depth profile, successfully truncating the length. This scenario is illustrated in Determine 20.
It is usually necessary to emphasis the incident mild within the crystal for SHG apps, given that effective technology of next harmonic gentle requires superior peak intensities, such as 109 W/cm2. When using femtosecond pulses with average energies in the nanojoule assortment, getting the necessary peak intensities can require smaller focal spots.
Pumped via the fourth harmonic of a Nd:YAG laser (at 266nm), a tunable OPO with signal wavelength range between 422nm and 477nm has been noticed by angle-tuning a kind I BBO crystal. Pumped by a 1mJ, 80fs Dye laser at 615nm, the OPA with two BBO crystals yields in excess of fiftyµJ (maximum one hundred thirtyµJ),
Nevertheless, there is not any 2nd purchase nonlinear result in alpha-BBO crystal due to the read more centrosymmetry in its crystal structure and therefore it's no use for next order nonlinear optical processes. As a substitute, alpha-BBO is widely employed for fabrication of polarizers, polarizing beam displacers, stage retarders, birefringent plates, and time hold off compensators Specifically These for UV and substantial ability lasers.
As might be mentioned down below, There exists a concentrating numerical aperture (NA) limitation on the SHG phase-matching system just analogous on the spectral period matching limitation talked about inside the prior part (
This fantastic-tuning ability ensures that BBO crystals can cater to each generic and very specialised needs with equivalent finesse.
When laser light-weight is concentrated to your place, the diameter on the beam waistline may be the focal spot size, and the speed at which The sunshine diverges with the beam waist is related to the Rayleigh vary (zR).
This text dives deep into the benefits and special Attributes of BBO crystal and its paramount value in successful frequency doubling and harmonics technology at 266nm.