With the continuous optimization and development of excitation light sources, Raman spectroscopy, as an important analytical method for substances, has greatly improved its detection performance. Especially in recent years, the research and development of laser excitation sources have significantly enhanced the detection performance of Raman spectroscopy, and it has been widely applied in the analysis of many samples. Due to its unique advantages such as high photoelectric conversion efficiency, controllable light frequency, wide operating temperature range, low excitation voltage, and stable output characteristics, it has gradually become the mainstream choice in the field of Raman detection.

By utilizing the excitation of electron-hole pairs, semiconductor lasers have obvious advantages such as small size, high efficiency, and long lifespan. By applying efficient frequency doubling technology to Nd:YAG crystals, the original 1064nm fundamental light is ingeniously converted into 532nm green light output. Through interaction with more closely spaced transition energies, especially the 532nm laser radiation, the Raman scattering cross-section can be effectively enhanced. With meticulous tuning for Raman detection, especially the ingenious balance of sensitivity and fluorescence suppression at the 532nm excitation wavelength, the optimal performance is achieved.

Compared to near-infrared lasers such as 785nm, the core advantage of 532nm lasers lies in their higher Raman scattering efficiency. Experimental data shows that the Raman signal intensity under 532nm excitation can be 5-8 times that of 785nm, making it highly feasible for the detection of trace substances. However, the 532nm laser is precisely located between the vibrational energy levels of most molecules and the electronic transition energy levels, avoiding direct photolysis of samples by ultraviolet lasers and effectively avoiding interference from long-wavelength fluorescence. Compared to other wavelengths, especially for the detection of the G peak (1580cm⁻¹) of graphene, the sensitivity of 532nm lasers has significantly improved.

By integrating thermoelectric cooling and grating feedback technology, modern 532nm diode lasers not only have excellent wavelength stability (up to ±0.1nm), but also have controllable output power fluctuations of less than 0.5%. This is particularly crucial for long-term Raman mapping stability. After continuous operation for 8 hours, the Raman characteristic peak shift does not exceed 0.2cm⁻¹, fully meeting the requirements of scientific research. Its portable and compact design allows it to be easily combined with various micro-Raman systems, and the adjustable power range reaches 1-500mW, fully meeting the needs of different samples.

Due to its good avoidance of the absorption peak of hemoglobin, the 532nm laser is the preferred laser for in vivo detection. With its high sensitivity, it can accurately identify and monitor trace ppb-level pollutants in the environment. In materials science research, especially for the precise identification of the number of layers of two-dimensional materials and microscopic stress analysis, the high-precision imaging capability of the 532nm Raman system is deeply relied upon. With the continuous advancement of semiconductor technology, the new distributed feedback (DFB) structure further compresses the line width to less than 1MHz, providing the possibility for high-resolution Raman.

As quantum dot laser technology gradually matures, 532nm diode lasers will achieve significant breakthroughs in output power (towards the watt level) and beam quality (M²<1.1). Through the deep integration with fiber optic probes and miniature spectrometers, it has pushed Raman detection equipment towards a more portable and intelligent direction, further consolidating its core position in analytical testing. At the same time, it has also promoted the wider application of Raman technology, which has a significant driving effect on the research and development of Raman.

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