Related Experiment Video
Updated: May 11, 2026
13:44
Simulation, Fabrication and Characterization of THz Metamaterial Absorbers
Published on: December 27, 2012
15.0K
Random temporal signal-based cavity ring-down spectroscopy: a noise-resilient approach for high-reflectance coating
Optics Express
|February 20, 2026
Summary
A new random temporal signal (RATS) cavity-ringdown spectroscopy (CRDS) method accurately measures ultra-high reflectance coatings. This technique offers improved precision and speed for optical applications.
Area of Science:
- Optical Engineering
- Metrology
- Materials Science
Background:
- Accurate characterization of high-reflectance optical coatings is critical for advanced optical systems.
- Conventional methods like spectrophotometry and pulsed cavity-ringdown spectroscopy (CRDS) have limitations at ultra-high reflectances (>99.99%).
Purpose of the Study:
- To present and experimentally verify a time-resolved CRDS technique using a random temporal signal (RATS) approach.
- To demonstrate the RATS-CRDS method's capability for precise reflectometry of ultra-high reflectance coatings.
Main Methods:
- Utilized a time-resolved CRDS technique with a randomly modulated laser signal (RATS).
- Performed numerical simulations and experimental measurements using a four-mirror cavity with reflectance >99.99%.
Main Results:
- The RATS-based CRDS method demonstrated smoother decay curves and enhanced precision compared to conventional pulsed CRDS.
- Achieved a 50x higher signal-to-noise ratio, improved photon throughput, and prevented mirror damage.
- Obtained comparable or superior accuracy in a significantly reduced acquisition time.
Conclusions:
- The RATS-CRDS method provides a robust and scalable solution for precision reflectometry of ultra-high reflectance coatings.
- This technique is suitable for demanding industrial and space-optics applications requiring accurate optical coating characterization.
Related Concept Videos
01:19Concept of Resonance and its Characteristics
If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano strings and many other musical instruments. Conversely, to achieve small-amplitude oscillations as in a car's suspension system, heavy damping is required. Heavy damping reduces the amplitude, but the tradeoff is that the system responds at more frequencies. Speed bumps and gravel roads prove that even a car's suspension system is not immune...
01:17Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
01:12Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
01:07Time-Domain Interpretation of PD Control
Proportional-Derivative (PD) control is a widely used control method in various engineering systems to enhance stability and performance. In a system with only proportional control, common issues include high maximum overshoot and oscillation, observed in both the error signal and its rate of change. This behavior can be divided into three distinct phases: initial overshoot, subsequent undershoot, and gradual stabilization.
Consider the example of control of motor torque. Initially, a positive...
Consider the example of control of motor torque. Initially, a positive...