Q: What is power density? How to calculate?
A: Power density = laser power per unit area, in W/cm². Basic formula: Power density = laser power (W) ÷ spot area (cm²). Advanced formula (known spot diameter): power density = P ÷ (π × R²).
Q: Can you give a calculation example?
A: 1000W laser, spot diameter 20mm: radius =1cm, area =3.14cm², power density ≈ 318W/cm². Select thermoelectric probe (damage threshold 10-20kW/cm²): Safe.
Similarly, 1000W, spot diameter 10mm: area = 0.785 cm ², power density ≈1274W/cm². The light spot is half smaller, and the power density has increased four times!
Q: What is the damage threshold?
A: Damage Threshold is the maximum power density that the probe can withstand, in W/cm² or kW/cm². When the damage threshold is exceeded, the probe surface will burn or rupture, resulting in permanent damage.
Q: What are the damage thresholds for each series of laser photovoltaics?
A: HS series (photodiode type): 5-50W/cm²; 5W-50W convective heat dissipation type: 5-10kW/cm²; air-cooled type: 6-10kW/cm²; kilowatt water-cooled standard type: 1- 6.5 kW/cm²; 10K-30K multi-layer cone type: 16kW/cm²; 80K-150K patented beam expansion type: 20kW/cm².
Q: How to avoid burning the probe?
A: ① Ensure that the power density is less than the probe damage threshold;② Reserve a safety factor of 2-3 times;③ The spot diameter is less than the aperture of the probe absorption surface;④ It is forbidden to hit the probe directly after focusing; ④ Regularly check whether the probe surface is damaged.
