Nanoradian angle sensor and in situ self-calibration

Area of Science:

• Metrology
• Optical sensing technologies
• Precision engineering

Background:

• Accurate angle measurement is critical in various scientific and industrial applications.
• Existing calibration methods often require expensive and complex reference instruments.
• Thermal drift and sensor instability can limit measurement precision.

Purpose of the Study:

• To develop a high-precision angle sensor with nanoradian (nrad) order accuracy.
• To introduce a novel in situ calibration system for angle sensors.
• To eliminate the need for accurate external reference instruments during calibration.

Main Methods:

• Elongating a critical-angle prism to enhance sensor sensitivity.
• Integrating a thermal controller to stabilize the light source and suppress thermal drift.
• Implementing an in situ self-calibration method to assess linearity error.

Main Results:

• The developed angle sensor exhibited a stability of 3 nrad over a 1-minute period.
• The in situ self-calibration method achieved a maximum repeatability error of approximately 35 nrad.
• The system operated effectively within a measurement range of 500 microradians (murad).

Conclusions:

• The proposed angle sensor and in situ calibration system offer a high-precision, self-contained solution for angle metrology.
• This approach significantly reduces calibration complexity and cost by removing the reliance on external reference standards.
• The demonstrated stability and repeatability pave the way for advanced applications requiring ultra-precise angular measurements.