Third Harmonic of High Power Lasers on the Basis of Yb- and Nd-doped Materials (343 nm, 355 nm)

Standard Components

The third harmonic of Nd:YAG, Nd:YVO₄ and Yb:YAG lasers has gained importance in the field of material processing, for measurement applications and as pump source for optical parametric oscillators. LAYERTEC manufactures a wide range of optics for 355 nm: single and multiple wavelength mirrors, separators, thin film polarizers and antireflection coatings. The coating designs shown here are calculated for 355 nm, but designs for 343 nm are available as well. In general, the coating designs are optimized according to customer specifications.

Turning Mirrors

Fig.1:Reflectance spectra of a turning mirror:
HRs (45°, 355 nm) > 99.9 % + HRp (45°, 355 nm) > 99.5 %

Standard Separators

Fig.2:Reflectance spectra of a standard separator reflecting the third harmonic and transmitting the second harmonic and the fundamental wave:
HRs (45°, 355 nm) > 99.9 % + HRp (45°, 355 nm) > 99.5 %
+ Rp (45°, 532 + 1064 nm) < 2 %
+ Rs (45°, 532 nm) < 5 % + Rs (45°, 1064 nm) < 10 %

Special Separators

Fig.3:Reflectance spectra of a special separator optimized for low reflectance at 1064 nm:
HRs (45°, 355 nm) > 99.9 % + HRp (45°, 355 nm) > 99.5 %
+ Rp (45°, 532 + 1064 nm) < 2 % + Rs (45°, 532 nm) < 5 %
+ Rs (45°, 1064 nm) < 2 %

Windows and Lenses

Fig.4:Reflectance spectra of a single wavelength AR coating for 355 nm optimized for AOI = 0°– 30°

Fig.5:Reflectance spectrum of a triple wavelength antireflection coating on Fused Silica for 355 nm, 532 nm and 1064 nm

Multiple Wavelength Mirrors

Fig.6:Reflectance spectra of a triple wavelength turning mirror for 355 nm, 532 nm and 1064 nm

Fig.7:Reflectance spectra of a dual wavelength turning mirror for 355 nm and 532 nm

Thin Film Polarizers

Fig.8:Reflectance spectra of a thin film polarizer for 355 nm:
HRs (55°, 355 nm) > 99.5 % + Rp (55°, 355 nm) < 2 %

The transmittance of p-polarized light can be optimized by angle adjustment. Tilting the polarizer by ±2° shifts the minimum of Rp to longer or shorter wavelengths which can improve the polarization ratio significantly.

Table 1:Technical Data of Mirrors and Separators

Type of Coating	IAD	IBS
Mirror for AOI = 0°	R > 99.9 %	R > 99.9 %
Turning Mirror	Rs > 99.9 %, Rp > 99 %	Rs > 99.95 %, Rp > 99.8 %
Separator AOI = 45°	Rs (355 nm) > 99.9 %	Rs (355 nm) > 99.9 %
	Rp (355 nm) > 99 %	Rp (355 nm) > 99.7 %
	Rs (532 nm) < 5 %	Rs (532 nm) < 2 %
	Rp (532 nm) < 2 %	Rp (532 nm) < 1 %
	Rs (1064 nm) < 10 %	Rs (1064 nm) < 2 %
	Rp (1064 nm) < 2 %	Rp (1064 nm) < 1 %

Third Harmonic of High Power Lasers on the Basis of Yb- and Nd-doped Materials (343 nm, 355 nm)