CRD mirrors

A CRD mirror typically refers to a mirror used in Cavity Ring-Down Spectroscopy (CRDS) systems.

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CRD Mirrors: CRD mirrors are the highly reflective mirrors used in the optical cavity of a CRDS setup. Their key characteristics include:

• High Reflectivity: Typically, the reflectivity of CRD mirrors is greater than 99.9%, often reaching 99.99% or higher to up 99.999%. High reflectivity ensures that light remains in the cavity for as long as possible, increasing the effective interaction path length and sensitivity.

• Low Loss: They are designed with minimal absorption and scattering losses to maintain the integrity of the light signal over many reflections.

• Wavelength-Specific: CRD mirrors are usually optimized for a specific wavelength or wavelength range corresponding to the laser source and the absorption bands of interest in the experiment.

• Substrate Material: Commonly made from materials like fused silica or BK7 or ULE, which are stable and have low thermal expansion.

• Coating: The reflective coating (often dielectric) is finely tuned to achieve the desired reflectivity and spectral response.

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Applications:

CRDS systems using CRD mirrors are widely used in fields like: 

• Environmental Monitoring: Detecting trace gases like CO₂, CH₄, and NO₂.

• Industrial Gas Analysis: Measuring impurities in high-purity gases.

• Fundamental Research: Studying molecular spectroscopy with high precision.

• Medical Diagnostics: Analyzing breath samples for biomarkers.