Related Experiment Video
Updated: Jun 7, 2026
12:21
Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators
Published on: April 4, 2016
Effects of curved mirrors in waveguide resonators
Applied Optics
|November 6, 2010
Summary
This study explores hybrid waveguide/free-space resonators for carbon dioxide (CO(2)) lasers, analyzing how design parameters affect resonator losses and mode quality. Novel geometries offer improved performance and stability compared to traditional designs.
Area of Science:
- Optics and Photonics
- Laser Physics
- Quantum Electronics
Background:
- Waveguide gas lasers, particularly carbon dioxide (CO(2)) lasers, are essential tools in various scientific and industrial applications.
- Previous research focused on simple resonator designs with plane mirrors near the waveguide ends.
- The need for advanced resonator designs to optimize laser performance and mode quality remains.
Purpose of the Study:
- To theoretically investigate hybrid waveguide/free-space resonators with square-bore guides and curved mirrors for CO(2) lasers.
- To analyze the impact of key design parameters on resonator mode losses.
- To evaluate the performance of a novel 7-W continuous-wave (cw) radio-frequency (rf)-excited CO(2) laser with a promising resonator geometry.
Main Methods:
- Theoretical analysis of resonator mode losses as a function of waveguide dimensions, mirror properties, and alignment.
- Experimental testing of a 7-W cw rf-excited CO(2) laser incorporating a hybrid resonator design.
- Comparison of the performance of novel resonator geometries with established designs.
Main Results:
- Resonator mode losses were shown to vary significantly with guide length and width, guide-to-mirror distance, mirror radius of curvature, and mirror tilt.
- A tested 7-W cw rf-excited CO(2) laser demonstrated unusually good near-transverse-electromagnetic-mode 00 (TEM(00)) transverse-mode quality.
- The common 3-reflector resonator design was found to be highly sensitive to minor misalignments in certain waveguide geometries, potentially compromising TEM(00) mode performance.
Conclusions:
- Hybrid waveguide/free-space resonators offer promising alternative geometries for CO(2) lasers, enabling improved mode quality and performance.
- Careful consideration of design parameters like mirror curvature and alignment is crucial for optimizing resonator stability and laser output.
- Novel resonator designs can overcome limitations of traditional configurations, leading to more robust and efficient laser systems.
Related Concept Videos
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:07Reflection of Waves
When a wave travels from one medium to another, it gets reflected at the boundary of the second medium. A common example of this is when a person yells at a distance from a cliff and hears the echo of their voice. The sound waves (longitudinal waves) traveling in the air are reflected from the bounding cliff. Similarly, flipping one end of a string whose other end is tied to a wall causes a pulse (transverse wave) to travel through the string, which gets reflected upon reaching the wall. In...
01:14Sound Waves: Resonance
Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical boundary conditions (i.e., has a node at each end). A node is defined as a fixed point where the string does not move. The symmetrical boundary conditions result in some frequencies resonating and producing standing waves, while other frequencies interfere destructively. Sound waves can resonate in a hollow tube, and the frequencies of the sound...
01:23Parallel Resonance
The parallel RLC circuit is an arrangement where the resistor (R), inductor (L), and capacitor (C) are all connected to the same nodes and, as a result, share the same voltage across them. The parallel RLC circuit is analyzed in terms of admittance (Y), which reflects the ease with which current can flow. The admittance is given by:
01:07Propagation of Waves
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.