The company has developed many kinds of infrared glass that permitting transmission of near-infrared light, mid-infrared light, far-infrared light at various bands.
Where, the transmission band, refractive index of near-infrared and mid-infrared glass is 370nm～6.7μm, 1.52～1.99 respectively. Their glass systems include silicate system, germinate system, calcium aluminate system, lead germinate system, lead niobate system, etc. They are mainly applied to airborne infrared pods, vehicle mounted infrared detection(Observe, aim), and infrared fairing, infrared window of other near-infrared, mid-infrared instruments. At present time, the company owns mid-infrared IRG1XX series and far-infrared IRG2XX series, etc.
Far-infrared glass is mainly applied to infrared detectors and devices at 8～14μm, and can be processed to far-infrared optical condenser lens with aspheric surface, components of prism group with spherical surface, glass windows. It can also be used as substrate material of external semiconductor GaAs, GaN or InGaN.
1）Product parameters of mid-inrared materials
2）Product parameters of far-inrared materials
1 Classification and designation of infrared optical glass
1.1 Principle of classification
Products are classified to mid-IR and far-IR optical glass according to the transmittance wavebands.
1.2 Designation methods of glass types
IRG203 refers to infrared optical glass which has transmittance at far-IR waveband and the sequence number of it is 03.
2 Optical properties
2.1 Infrared refractive index
Infrared refractive index refers to the velocity of infrared light in the air as compared to that in the medium by the municipality. The testing principle of arbitrary deflection angle method is adopted to measure incident angle i, refraction angle φ and sample angle A. According to formula n=(sin2φ+2sinφcosAsini+sin(2i))1/2/ sinA, we can obtain refractive index n of every band. The measurement accuracy is ±2×10-4.
2.2 Infrared dispersion coefficient υe and υ10.6
Refractive index of different wavelength in a medium is unequal. Infrared dispersion coefficient means the deviations of refractive index of different wavelength. The dispersion coefficient of mid-wave material (0.3～8um) which allows visible light to go through is expressed by υe or υd, while the long wave material (1～14um) which is nontransparent to visible light is expressed by υ10.6, and υ10.6 can be calculated by the following equation:
2.3 Calculate constant
The calculate constant of IR optical glass can be obtained by Herzberger formula:
IR dispersion coefficients A, B, C, D, E, F can be calculated according to the refractive indice of testing bands. IR dispersion coefficients A, B, C, D, E, F differ from glass types, and they are listed in the corresponding performance data sheets。
2.4 Infrared transmittance τ
Infrared transmittance is measured by Fourier transformation methods. Using functions to process the signals collected by detector through computer, we can obtain infrared absorption spectrogram of the same light strength with classic infrared spectrometer depending on frequency can be obtained.
3 Dielectric constant
Measure dielectric constant according to the recommended methods for capacitivity and dielectric loss factor of electroinsulating material at power frequency, audio frequency and high frequency (including meter wavelength) in GB/T 1409-2006.