Quartz plates are a specific type of glass plate that is manufactured using high-purity silicon dioxide (SiO₂). It is evident that, due to their distinctive physical and chemical properties, they occupy a unique position in the field of optical instruments. Its function is not only reflected in the optical path transmission, but also directly affects the measurement accuracy, stability and application range of the instrument. The following analysis is a detailed investigation of the specific role of quartz plates in optical instruments, commencing with an examination of their fundamental characteristics.

1. The core characteristics of quartz plates

(1) Ultra-high ultraviolet light transmittance

Ordinary glass absorbs ultraviolet light (UV) with a wavelength between 200 and 350 nanometres (nm) strongly, while quartz plates have a light transmittance of over 90% in the ultraviolet region (180 to 400 nm) and even extend to the deep ultraviolet area. It is one of the few transparent materials capable of transmitting deep ultraviolet light.

(2) High-temperature resistance and chemical stability

The softening point of quartz is approximately 1700℃. It can operate for a long time at 1000℃ and is not prone to react with acids and alkalis (except hydrofluoric acid). It can withstand corrosion and high temperatures in extreme environments.

(3) Low coefficient of thermal expansion

The coefficient of thermal expansion of quartz is only 1/10 that of ordinary glass, and its dimensional deformation is extremely small when the temperature changes, ensuring the stability of the optical path.

2. The specific role of quartz plates in optical instruments

(1) Spectral analysis instrument: The core component for precise detection

In equipment such as ultraviolet-visible spectrophotometers, fluorescence spectrometers, and atomic absorption spectrometers, quartz plates are the key carriers for sample detection.

Quartz cuvette: Quartz plates are utilized for the analysis of samples within the ultraviolet spectrum. Ordinary glass cuvettes absorb ultraviolet light, resulting in measurement errors. Conversely, quartz cuvettes ensure that ultraviolet light passes through the sample without loss, thereby obtaining accurate absorbance data.

The protective plate for the combustion head of the atomic absorption spectrometer: The flame temperature of atomic absorption can reach temperatures in excess of 2000°C. The high-temperature resistance of quartz plates enables them to protect the burner head from damage caused by high temperatures while not interfering with the light absorption signal of atoms.

(2) Laser instruments: The key to optical path transmission and resonant cavity

The laser system is highly demanding in terms of light transmittance and high-temperature resistance of optical path components. Quartz plates play a crucial role in this regard.

Laser resonator window: In the laser system, the quartz window can efficiently transmit the laser while withstanding the high temperature generated by the laser, preventing component deformation and affecting the stability of the resonant cavity.

(3) Optical measurement and interferometry instruments: The foundation for precision assurance

High-precision optical measurement instrumentation, including interferometers and ellipsometers, must meet stringent stability requirements to ensure accurate and reliable measurements. The low coefficient of thermal expansion of quartz plates makes them an ideal choice.

Standard components of an interferometer: In an interferometer, quartz plates can be used as reference standard components in the optical path. When the temperature changes, the size of the quartz plate remains almost unchanged, ensuring the stability of the interference fringes and thereby improving the measurement accuracy.

Optical calibration equipment: Calibration rods or standard plates made of quartz can be used to calibrate the optical path deviation of optical instruments. Their stable physical properties ensure the reliability of the calibration results.

3. Conclusion

Quartz plates offer unique optical, thermal and chemical properties, making them valuable components in a variety of optical instruments. They function as “optical path carriers,” “protective barriers,” and “precision guarantees,” contributing to the performance and reliability of these instruments. From the precise detection of spectral analysis to the efficient transmission of laser systems, quartz plates are used in a variety of optical instruments. The development of optical technology has led to significant advancements in the processing accuracy of quartz plates. These plates are set to play a more prominent role in high-end optical instruments, providing a robust material foundation for advancements in the optical field.