многоуровневое название:
1. Введение
1.1 Определение длины волны
1.2 Importance of measuring wavelength
2. Methods of measuring wavelength
2.1 Spectrometer
2.1.1 Principle of spectrometer
2.1.2 How spectrometer measures wavelength
2.2 Interference-based techniques
2.2.1 Diffraction grating
2.2.2 Fabry-Perot interferometer
3. Applications of measuring wavelength
3.1 Спектроскопия
3.1.1 Analyzing chemical composition
3.1.2 Studying molecular structure
3.2 Телекоммуникации
3.2.1 Optical fiber communication
3.2.2 Wavelength-division multiplexing
4. Challenges in measuring wavelength
4.1 Accuracy and precision
4.1.1 Calibration of instruments
4.1.2 Sources of measurement errors
4.2 Measurement range
4.2.1 Limitations of different measurement techniques
4.2.2 Overcoming wavelength range limitations
5. Заключение
