W. C. Solomon

University of Illinois, Urbana-Champaign | UIUC · Department of Aerospace Engineering

Experiments[1] with Electric Oxygen-Iodine Laser (ElectricOIL) heat exchanger technology have demonstrated improved control of oxygen atom density and thermal energy, with minimal quenching of O2(a1Δ), and increasing small signal gain from 0.26% cm-1 to 0.30% cm-1. Heat exchanger technological improvements were achieved through both experimental an...

Over the last decade new advanced gas lasers have emerged as possible candidates for high power laser systems that may supplant more conventional chemical and gas laser systems. Among these are the electric oxygen-iodine laser (ElectricOIL), the diode pumped alkali laser (DPAL), the exciplex pumped alkali laser (XPAL), and the optically pumped meta...

Continuing experiments with electric oxygen-iodine laser (ElectricOIL) technology have significantly increased laser power output by increasing the product of gain and gain-length, $g_{0}L$. The authors report on progress with recent ElectricOIL devices utilizing a new concentric discharge geometry with improved ${\rm O}_{2}(a^{1}\Delta)$ productio...

The authors report the development of an electric oxygen-iodine laser with higher output using a larger product of gain and gain length, g 0 L . A factor of 4.4 increase in laser power output on the 1315 nm atomic iodine transition was achieved with a factor of 3 increase in gain length. I ( P 2 1 / 2 ) is pumped using energy transferred from O 2 (...

Continuing experiments with Electric Oxygen-Iodine Laser (ElectricOIL) technology have significantly increased laser power output by increasing the product of gain and gain-length, g0L. The authors report on progress with recent ElectricOIL devices utilizing a new concentric discharge geometry with improved O2(a1▵) production at higher discharge op...

Continuing experiments with Electric Oxygen-Iodine Laser (EOIL) technology have significantly increased laser power output by increasing the product of gain and gain-length, g0L. Increasing the system size by a factor of 3 resulted in a 5-fold increase in laser output on the 1315-nm transition of atomic iodine. The peak output power observed was 53...

We present quantitative analysis of image sequences of multi-stream injection nozzle flows with several different injection geometries in an experiment simulating mixing in a chemical oxygen-iodine laser. To visualize mixing, image sequences were acquired with planar laser-induced fluorescence (PLIF) in iodine that was injected into the main flow....

Several variants of an ejector mixing nozzle concept for a high-pressure chemical oxygen-iodine laser (COIL) have been experimentally tested. To obtain a better understanding of how much performance enhancement could be expected with increased mixing and to facilitate a larger parametric study we utilized the quasi-1D BLAZE-IV model to simulate the...

A variant of an ejector-mixing nozzle for a chemical oxygen–iodine laser was experimentally tested with notched starlet ejectors. Cold-flow planar laser-induced fluorescence measurements indicated that the starlets provide faster mixing. Hot-flow testing demonstrated that the starlet design improved laser performance by 20–30% above the basic cylin...

Experiments and modelling have led to continued enhancements in the electric oxygen–iodine laser system. This continuous wave laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O 2 (a) in a radio-frequency discharge in an O 2 /He/NO gas mixture. New discharge geometries have led to improvements in O 2 (a) prod...

Experiments and modeling have led to a continuing evolution of the Electric Oxygen-Iodine Laser (ElectricOIL) system. A new concentric discharge geometry has led to improvements in O2(a) production and efficiency and permits higher pressure operation of the discharge at high flow rate. A new heat exchanger design reduces the O2(a) loss and thereby...

Lee H. Sentman III (1937-2010) contributed to many fields in aerospace sciences for nearly five decades before his passing. He pursued his passion for flight and aeronautics through education, science, teaching, and decades of flight experience. He specialized in non-equilibrium gas kinetic flows and was the first to demonstrate the importance of q...

Experiments and modeling have led to a continuing evolution of the Electric Oxygen-Iodine Laser (ElectricOIL) system. This continuous wave (cw) laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O2(a) in a radio-frequency (RF) discharge in an O2/He/NO gas mixture. New discharge geometries have led to improveme...

The authors observed 95% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine for only a 50% increase in gain length (5.1 cm to 7.6 cm), flow rates, and discharge input power, making use of a large volume 16-mm gap transverse discharge. A gain of 0.26% cm -1 was obtained and the laser output power was 55 W in a stab...

A variant of an ejector mixing nozzle for a chemical oxygen-iodine laser (COIL) was experimentally tested with notched "starlet" ejectors. Cold flow planar laser induced fluorescence (PLIF) measurements indicate that the starlets provide faster mixing. Hot flow testing demonstrated that the starlet design improved laser performance by 20-30% above...

Experiments and modeling have led to continued enhancements in the Electric Oxygen-Iodine Laser (ElectricOIL) system. This continuous wave (cw) laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O 2 (a) in a radio-frequency (RF) discharge in an O 2 /He/NO gas mixture. New discharge geometries have led to impro...

Experiments and modeling have led to continued enhancements in the Electric Oxygen-Iodine Laser (ElectricOIL) system. This continuous wave (cw) laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O 2 (a) in a radio-frequency (RF) discharge in an O 2 /He/NO gas mixture. New discharge geometries and increases in...

The mechanisms of the mixing between separate flows are of high interest in order to increase the efficiency of processes that rely on well mixed flows. Mixing of three flows was examined, where two of the flows were in an underexpanded state, and the third near-ideally expanded. One of the underexpanded flows served as a driver gas for the mixing...

Herein the authors report on the demonstration of an 87% enhancement in cw laser power on the 1315 nm transition of atomic iodine via a 100% increase in the resonator mode volume. O 2 ( a 1 Δ ) is produced by a single rf-excited electric discharge sustained in an O 2 – He – NO gas mixture flowing through a rectangular geometry, and I ( P 2 1 / 2 )...

Die Reaktion von Stickstoffatomen mit NF2 eignet sich zur Erzeugung von Fluoratomen in einer inerten Umgebung. Die Konzentration der Fluoratome kann durch Titration mit NOCl bestimmt werden. Über die Messung der Geschwindigkeitskonstante der Reaktion F + H2 → HF + H wird berichtet.Fluorine atoms can be produced by reaction of nitrogen atoms with NF...

Experiments and modeling have led to continued enhancements in the Electric Oxygen-Iodine Laser (ElectricOIL) system. This continuous wave (cw) laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O2(a) in a radio-frequency (RF) discharge in an O2/He/NO gas mixture. New discharge geometries have led to improveme...

Experiments and modeling have led to continued enhancements in the Electric Oxygen-Iodine Laser (ElectricOIL) system. This continuous wave (cw) laser operating on the 1315 nm transition of atomic iodine is pumped by the production of O2(a) in a radio-frequency (RF) discharge in an O2/He/NO gas mixture. New discharge geometries have led to improveme...

Herein the authors report on the demonstration of gain and a continuous-wave laser on the 1315 nm transition of atomic iodine using the energy transferred to I(2 P 1/2) from O 2 (a 1) produced by both radio-frequency and microwave electric discharges sustained in a dry air–He–NO gas mixture. Active oxygen and nitrogen species were observed downstre...

The mechanisms of the mixing between separate flows are of high interest in order to increase the efficiency of processes that rely on well mixed flows, such as combustion. In this paper, Planar Laser Induced Fluorescence (PLIF), in two perpendicular planes, of an Iodine-seeded flow was used to visualize and quantify the mixing of three flows due t...

Laser action at 1315 nm on the I( 2 P1/2) → I( 2 P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a 1 ∆) produced using a low-pressure electric discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds signific...

Herein the authors report on the demonstration of a 95% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine via a 50% increase in gain length, flow rates, and discharge power. O2(a 1Δ) is produced by a single radio-frequency-excited electric discharge sustained in an O2–He–NO gas mixture flowing through a rectangul...

Recent experiments have led to continued improvements in the hybrid Electric Oxygen-Iodine Laser (ElectricOIL) system that significantly increased the discharge performance, supersonic cavity gain, and laser power output. Experimental investigations of radio-frequency discharges in O 2 /He/NO mixtures in the pressure range of 10-50 Torr and power r...

Recent investigations of an Electric Oxygen-Iodine Laser system have shown that computational modeling over-predicts the laser power output measured in experiments for similar gain conditions. To help resolve this discrepancy, detailed 2-axis mapping of gain and gain recovery measurements downstream of an operating laser cavity were performed. Mode...

Recent investigations of an electric oxygen-iodine laser system have shown that computational modeling overpredicts the experimentally measured power output for similar gain conditions. This discrepancy is potentially due to an unknown reaction that competes with the forward pumping of I�2P1/2� by O2�a 1��. Measurements of gain recovery downstream...

Experimental investigations of radio-frequency discharges in O2/He/NO mixtures in the pressure range 1–100 Torr and power range 0.1–1.2 kW have indicated that O2(a 1Δ) production is a strong function of geometry, excitation frequency, pressure and diluent ratio. The goal of these investigations was maximization of both the yield and the flow rate (...

Herein the authors report on the demonstration of gain and a continuous-wave laser on the 1315 nm transition of atomic iodine using the energy transferred to I(2P1/2) from O2(a1Δ) produced by a radio-frequency-excited electric discharge sustained in a dry air-He–NO gas mixture. Active oxygen and nitrogen species were observed downstream of the disc...

Herein the authors report on the demonstration of a 70% enhancement in gain and 98% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine via an increase in flow rates and pressure using multiple discharges in an electric oxygen-iodine laser. O ₂(a ¹Δ) is produced by two parallel radio-frequency...

Experimental investigations of radio-frequency discharges in O 2/He/NO mixtures in the pressure range of 1-100 Torr and power range of 0.1-2.5 kW have indicated that O2(a1Δ) production is a strong function of geometry, pressure and diluent ratio. The goal of these investigations was maximization of both the yield and flow rate (power flux) of O2(a1...

Experimental investigations of radio-frequency discharges in O2/He/NO mixtures in the pressure range of 1-100 Torr and power range of 0.1-1.2 kW have indicated that O2(a1Delta) production is a strong function of geometry, excitation frequency, pressure and diluent ratio. The goal of these investigations was maximization of both the yield and flow r...

Herein the authors report on the demonstration of a 50% enhancement in gain and 38% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine through the addition of a secondary discharge to predissociate the molecular iodine in an electric oxygen-iodine laser. In the primary discharge the O2(a 1Δ) is produced by a radio...

Laser oscillation at 1315 nm on the I(2P1/2)-->I(2P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a1Delta) produced using a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited...

Recent experiments have led to improvements in the hybrid Electric Oxygen-Iodine Laser (ElectricOIL) system that significantly increased the discharge performance, supersonic cavity gain, and laser power output. The continuous wave laser operating on the I( 2 P 1/2 ) → I( 2 P 3/2 ) transition of atomic iodine at 1315 nm was pumped by the production...

In the hybrid electric discharge Oxygen-Iodine laser (ElectricOIL), the desired O2(a1Δ) is produced using a low-to-medium pressure electric discharge. The discharge production of atomic oxygen, ozone, and other excited species adds higher levels of complexity to the post-discharge kinetics which are not encountered in a classic purely chemical O2(a...

Laser oscillation at 1315 nm on the I(2P1/2) ? I(2P3/2) transition of atomic iodine has been obtained by a near resonant energy transfer from O2(a1Delta) produced using a low-pressure oxygen/helium/nitric-oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited...

Recent experiments have led to improvements in the hybrid Electric Oxygen-Iodine Laser (ElectricOIL) system that significantly increased the discharge performance, supersonic cavity gain, and laser power output. The continuous wave laser operating on the I(2P1/2) → I(2P3/2) transition of atomic iodine at 1315 nm was pumped by the production of O2(a...

Herein the authors report on the demonstration of a continuous-wave laser in subsonic flow on the 1315 nm transition of atomic iodine using the energy transferred to I() from O2(a ) produced by a radio-frequency-excited electric discharge. The electric discharge was sustained in an O2–He–NO gas mixture. Downstream of the discharge, cold gas injecti...

In an electric discharge oxygen-iodine laser, laser action at 1315 nm on the I (²P_1/2)→ I (²P_3/2) transition of atomic iodine is obtained by a near resonant energy transfer from O ₂(a ¹Δ) which is produced using a low-pressure electric discharge. The discharge production of atomic ox...

Recent experiments have led to improvements in the hybrid Electric Oxygen-Iodine Laser (ElectricOIL) system that significantly increased the laser power output. The continuous wave laser operating on the I(2P 1/2) → I(2P3/2) transition of atomic iodine at 1315 nm was pumped by the production of O2(a 1Δ) in a radio-frequency discharge in a He/O2 mix...

In an electric discharge Oxygen-Iodine laser (ElectricOIL), the desired O 2 (a 1 ∆) is produced using a low–to-medium pressure electric discharge. The discharge production of atomic oxygen, ozone, and other excited species adds higher levels of complexity to the post–discharge kinetics which are not encountered in a classic purely chemical O 2 (a 1...

chemical O 2 (a 1 Δ) generation system. In this paper we present post-discharge modeling results obtained using a modified version of the Blaze-II chemical laser code. The effects of proposed chemical kinetic reactions on post discharge kinetics were studied and simulations were compared with experimental data. The modified Blaze-II code was used t...

In this paper we report on studies of a continuous wave laser at 1315 nm on the I( 2 P 1/2 ) → I( 2 P 3/2 ) transition of atomic iodine where the O 2 (a 1 Δ) used to pump the iodine was produced by a radio frequency excited electric discharge. The electric discharge was sustained in He/O 2 and Ar/O 2 gas mixtures upstream of a supersonic cavity whi...

Laser action at 1315 nm on the I (²P_1/2)→ I (²P_3/2) transition of atomic iodine is conventionally obtained by a near-resonant energy transfer from O ₂(a¹Δ) which is produced using wet-solution chemistry. The difficulties in chemically producing O ₂(a¹Δ) has moti...

Laser action at 1315 nm on the I(²P₁2/)→I(²P₃2/) transition of atomic iodine is conventionally obtained by a near-resonant energy transfer from O₂(a¹Δ) which is produced using wet-solution chemistry. The system difficulties of chemically producing O₂(a¹Δ) have m...

Laser action at 1315 nm on the I(²P_1/2)→I(²P_3/2) transition of atomic iodine is conventionally obtained by a near-resonant energy transfer from O ₂(a¹Δ) , which is produced using wet-solution chemistry. The system difficulties of chemically producing O ₂(a¹Δ) ha...

Preliminary measurements of the yield of O 2 (1 Δ) as a function of power absorbed in an RF discharge are presented. The yield is deduced from measurements of gain/absorption using the PSI Iodine Scan diagnostic coupled with a data reduction technique originally developed by PSI. A more formal presentation of the method of deducing the yield is pro...

Theoretical studies have indicated that sufficient fractions of O₂(¹Δ) may be produced in an electrical discharge that will permit lasing of an electric discharge oxygen-iodine laser (ElectriCOIL) system. Results of those studies along with more recent experimental results show that electric excitation is a very complicated pr...

Theoretical and experimental studies haveindicated that fractions of O2(1Δ) can be produced in anelectrical discharge that may permit lasing of an electricdischarge oxygen-iodine laser (ElectriCOIL) system,possibly in conjunction with the injection of predissociatediodine. Results of those studies along withmore recent experimental results show tha...

Modeling studies have shown that fractions of O2( 1 ∆ ) may be produced in an electrical discharge that will enable oscillation of a chemical oxygen-iodine laser system in conjunction with injection of pre-dissociated iodine. Results of those studies along with recent experimental results indicate that generation of O2( 1 ∆ ) can be optimized by th...

Theoretical studies have indicated that fractions of O 2 (1 D) can be produced in an electrical discharge that may permit lasing of an electric discharge oxygen-iodine laser (ElectriCOIL) system, possibly in conjunction with the injection of pre-dissociated iodine. In this paper, recent computations in the ElectriCOIL system are presented, includin...

Theoretical studies have indicated that fractions of O2(1Δ) may be produced in an electrical discharge that will permit lasing of an ElectriCOIL system in conjunction with injection of pre-dissociated iodine. Results of those studies along with more recent experimental results show that electric excitation is a very complicated process that must be...

Detailed studies of mechanisms for producing electrically initiated COIL lasers were previously presented. Results of those studies along with more recent experimental results show that electric excitation is a very complex process that must be investigated with advanced diagnostics. Theoretical studies indicate that fractions of O2( 1 Δ) may be pr...

Theoretical studies have indicated that sufficient fractions of O 2 (1 D) may be produced in an electrical discharge that will permit lasing of an electric discharge oxygen-iodine laser (ElectriCOIL) system in conjunction with injection of pre-dissociated iodine. Results of those studies along with more recent experimental results show that electri...

Over the past six years we have been conducting detailed studies of a family of closely related supersonic mixing nozzles. These nozzles have performed well in experiments with the VertiCOIL laser. Subtle design changes in these nozzles lead to highly predictable results when compared to the complete CFD calculations for the three designs under stu...

Advanced chemical iodine laser technology will logically include novel all gas phase generation techniques for an iodine energy donor and the injection of atomic rather than molecular iodine. Candidate methods are discussed for the creation of an all gas phase energy donor as well as for injecting atomic iodine. This research will lead directly to...

A chemical oxygen-iodine laser (COIL), the VertiCOIL device, was transferred from the Air Force Research Laboratory (AFRL) to the University of Illinois at Urbana-Champaign (UIUC) and made operational. The performance of the high-power VertiCOIL laser was measured with nitrogen diluent, New nozzle designs were investigated and implemented to optimi...

The chemical oxygen-iodine laser (COIL) is a high power, fiber deliverable tool, which can be used for a number of different industrial applications. COIL is of particular interest because of its short fiber deliverable wavelength, high scaleable continuous wave power, and excellent material interaction properties. In past research the University o...

Engineers at CU Aerospace (CUA) and The University of Illinois at Champaign-Urbana (UIUC) have developed an innovation to the classical chemical oxygen-iodine laser (COIL) singlet oxygen generator (SOG) based on discharge excitation of molecular oxygen. A number density of ~2.1x10 15 of O2( 1 Σ) was measured for a total O2 flow rate of 7 mmol/s and...

This paper investigates advanced mixing nozzle concepts for the chemical oxygen-iodine laser (COIL) that will significantly improve the chemical efficiency of such systems. It is believed that innovative nozzle design improvements should increase COIL chemical efficiencies. This technology will logically include injection of atomic rather than mole...

The chemical oxygen-iodine laser (COIL) is a high power, fiber deliverable tool, which can be used for a number of different industrial applications. Commercialization issues are discussed along with potential markets. Technological development efforts are underway to make this device usable for long run times and economically viable. New nozzle in...

The chemical oxygen-iodine laser, COIL, presents a significant challenge for analytical models due to the complex couplings between fluid dynamics and chemistry that occur in the system. This paper demonstrates the use of the CFD code GASP as an analytical tool to model these complexities. A conservative, multispecies diffusion model has been devel...

The rate constants for the hydrogen three-body collisional recombination reaction with atomic and molecular hydrogen acting as third bodies have been determined by numerous investigators during the past 30 yr, but these rates exhibit significant scatter. The discrepancies in the rate constants determined by different investigators are as great as t...

The efflux composition characteristics of an experimental fuel-rich gas generator have been modeled with a detailed hydrocarbon kinetics package that includes the effects of liquid droplet vaporization. The chemical reaction mechanism, consisting of 107 chemical species and 642 reversible reactions, is capable of describing a complex kerosene-type...

The impact of the uncertainty in the knowledge of hydrogen recombination rates on the specific impulse (Isp) delivered by a 30-klb(f) NTR has been determined for chamber pressures and temperatures from, respectively, 20 to 1000 psia and 2700 to 3300 K. The uncertainty in the rate constants is as great as two orders of magnitude in the range 1500-35...

Interest in the DF-CO 2 transfer chemical laser (TCL) is stimulated by its potential to yield high specific efficiencies and high gain coefficients at high optical cavity pressures. Previous technology studies of the DF-CO 2 TCL for the most part have been limited to operation at cavity pressures of 100 torr or less. Recently, high pressure operati...

A computer model of the DF-CO 2 CW transfer chemical laser (TCL) which treats the first nine vibrational states of DF and the first thirty-nine vibrational states of CO 2 is described in detail. Information theory, as it now exists, was used to correlate the large number of possible energy transfer processes involving the CO 2 molecule with the rat...

Experimental data are presented relative to attempts to induce laser oscillations in the vicinity of 5578 A in a chemically prepared tin oxide medium. Atomic tin was first prepared by shock-heating mixtures of SnCl/sup 4/ in argon. The plenum gases were accelerated through a nozzle bank and molecular N/sup 2/O was injected into the supersonic flow...

The sensitivity of laser performance predictions to the approach used to define critical input parameters is examined. These include: (1) entrance conditions to cavity, i.e., composition, temperature, Mach number, pressures and their distribution across the boundary layers, (2) effective pressure distribution through the laser cavity, (3) mirror re...