Laser Technologies                                           

Research Objectives

  • Research & development of novel optical sensors to make measurements that are not currently possible
    • New laser sources/detection techniques for measurement of temperature, pressure, velocity, species concentration
  • Combusion, atmospheric, and industrial research employing optical measurements
    • Fundamental characterization of difficutl environments
    • Rapid system control and optimization

Approach: Laser Spectroscopy

A laser that gives off a light intensity that goes through a sample, reflects, and then enters the detectors

Light absorption by molecules is given by I/Io = exp(-alpha), where I is light intensity and alpha is absorbance. Absorbance varies with concentration, temperature, and pressure. 

A graph of absorbance vs optical frequency vs wavelength where increasing concentration of carbon dioxide shows increasing absorbance at a wavelength of approximately 1606.5 nanometers.a graph of absorbance vs wavelength and optical frequency that shows that at lower frequencies, increasing room temperature causes an increase in absorbance; however, at higher frequencies, increasing room temperature causes a decrease in absorbance.

Laser Tools

Frequency Comb Lasers

  • Emit >10^5 wavelength elements spanning 100s of nanometers of spectrum with picometer spacing
  • Boradband spectroscopy allows for detection of multi-species or broad absorbers (high P gas, liquids)
  • Together with NIST, we've built the first fieldable dual frequency comb spectrometer

a frequency comb lasera graph of intensity vs wavelength that shows sinusoidal behavior across the spectrum

Diode Lasers

  • Robust, compact, low cost
  • Single wavelenth output, rapidly tunable over small range
  • Capable of rapid, sensitive measurements (>100 kHz)

a diode laser, which is about the same size as a quartera graph of intensity vs wavelength that shows a single wavelength output at 1390 nm with an intensity of 30 dB

Atmospheric Sensing

Our laboratory develops and fields frequency comb laser-based sensors for gas species and turbulence measurements in the atmosphere. We combine our sensor measurements with computational models to develop a better understanding of atmsopheric processes or in the example below, to locate gas sources.

Example: Methane Leak Detection

Mobile remote sensing laboratory providing field measurement of methane absorption. Leaks as small as 1/6 the human breathing rate have been detected from 1 km.

a map showing that the wind is perpendicular to the downwind and upwind retro between the methane leak and the trailera graph of methane concentration versus time that shows an upside down parabola as the leak progressesan instrument used to measure the concentration of methane

High Temperature Sensing

We are developing and deploying sensors to improve our understanding of high temperature environments from combustion to exoplanet atmospheres.

Example: High Temperature Absorption Database for Combustion

Controlled laboratory measurement of water absorption under gasifier conditions to build database for interpretation of subsequent field-deployed sensors.

the cell, detector, and acquisition setup at the CU Rieker lab, which shows the bran link (frequency comb light from NIST) running into the phase correction. On the lab bench is the gas handling, which is connected to the optics and furnace

Example: From Nobel Prize to Power Plant

We are the first lab to deploy frequency combs for a practical combustion measurement. In this case, a 16 MW gas turbine on campus.

a diagram of a power plant that shows a dual comb spectrometer with a reference laser and spectral filter running with a combustor steam injection into an exhaust duct, a heat exchanger, and then into the environment

Industrial Sensing

We work with industrial/scientific partners to characterize complex environments and to develop sensor-based control in these environments

Example: Industrial Burner Characterization

  • Characterize the thermodynamic properties of the flames and heated gases above industrial burners used for material processing
  • Understand how the introduction of materials affect the flow fields

a catalytic burnera ribbon burner

  • Develop advanced methods to fuse experimental data and computational fluid dynamics simulations

a measurement that shows a range of mean temperature