Mountain Scholar

Mountain Scholar is an open access repository service that collects, preserves, and provides access to digitized library collections and other scholarly and creative works from Colorado State University and the University Press of Colorado. It also serves as a dark archive for the Open Textbook Library.

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Colorado State University, Fort Collins 28655
Explore the Colorado State University community’s scholarly output as well as items from the University at large and the CSU Libraries.
Open Textbook Library Archive 1790
A limited number of titles are available here. To see all OTL titles, please visit the Open Textbook Library at https://open.umn.edu/opentextbooks. Only Open Textbook Library staff have access to all OTL Archive titles held in Mountain Scholar.
University Press of Colorado 1106
Access is limited to University Press of Colorado members. Non-members: to purchase books, please visit https://upcolorado.com/.

Recent Submissions

Access status: Open Access ,
Fabrication and characterization of electrically pumped VCSEL based intracavity fluidic biosensor
(2002) Yu, Tao, author; Wilmsen, Carl, advisor; Lear, Kevin, committee member; Field, Stuart, committee member
There is an increasing need to quickly and cheaply detect the presence of biological agents introduced into the atmosphere by terrorists or on the battlefield. In order to accomplish this requires a biosensor and a method of integrating it with electronics and an alarm or display. The overall device must be small, easily manufactured and simple to use in order that it be sufficiently portable to allow being carried in many different types of situations. This thesis reports the fabrication and characterization of such a sensor based on an electrically pumped vertical-cavity surface-emitting laser (VCSEL). The prototype biosensor structure reported here is composed of a "half VCSEL" separated from a glass top plate coated with a dielectric distributed bragg reflector (DBR) mirror by a ~ 5 μm thick photoresist spacer. Simulations indicate that the emission wavelength for the sensor is shifted quasi-continuously with respect to the change of the cell refractive index and/or the fluidic cavity thickness. Fabrication of the VCSEL biosensor required the development of suitable techniques for forming the fluidic cavity, a fluid delivery system, proper sealing and forming the VCSEL. All of these were accomplished. The fluidic cavity, which provides suitable spacing and fluid seal, was formed by heating patterned photoresist at 90 °C with external force applied. The fluid was introduced into the VCSEL cavity from a capillary tube butted up against the side of the cavity. The tube/cavity connection was successfully sealed with a deposited epoxy gasket. Forming a suitable n-ohmic contact was the most difficult step in VCSEL fabrication because the n mirror is very thin. The assembled structure was shown to emit light but apparently does not lase. The functionality of the biosensor was demonstrated by the presence of a 3.2 nm wavelength shift of the ~840 nm peak when DI water was injected into the empty fluidic cavity. The emission spectra are complex and the further study and analysis are required to interpret the measurements.
Access status: Open Access ,
Fabrication and characterization of high-speed oxide-confined vertical cavity surface emitting lasers
(2002) Al-Omari, Ahmad Nasser, author; Lear, Ken, advisor; Wilmsen, Carl, committee member; Field, Stuart, committee member
The necessities for communication-network services such as database queries, remote education, telemedicine and videoconferencing have increased the need for highspeed communication systems with greater bandwidth. Faster single channel systems require faster VCSELs, and thus it is important to develop high-speed VCSELs, since they are suited for LAN application in a number of ways. High-Speed Oxide-Confined Vertical-Cavity Surface Emitting Lasers were fabricated in this research. Standard and repeatable fabrication steps were developed. Important fabrication steps that enhance the oxide-confined VCSELs modulation frequency were adopted. Photosensitive and non-photosensitive polyimides were investigated. Metal-to-polyimide adhesion was improved. Adhesion strength was examined using scotch tape. The measured threshold voltage and current of a fabricated VCSEL with 28μm diameter and 7μm oxide-confined aperture were as low as 1.5V and 0.4mA, respectively. The active area resistance at zero bias was found to be 98Ω. Optical modulation frequency of 17.0GHz for a VCSEL with 28μm diameter and 7μm oxide-confined aperture was observed. An equivalent circuit model for high-speed oxide-confined VCSELs, which is important for designing high-speed interfacing circuits to VCSELs, was obtained. Ion implanted VCSELs were investigated and simulated using the Trim and Pspice softwares. Eon implantation is expected to reduce the active area capacitance from 135fF to 83fF. As a consequence, the electrical –3dB frequency will increase to 32GHz, which represents about 30% improvement.
Access status: Open Access ,
Economic analysis of groundwater curtailment in Colorado's Republican River basin
(2025-12) Hill, Rebecca, author; Manning, Dale T., author; Suter, Jordan, author; Vomitadyo, Innocent, author; Colorado Water Center, publisher
Access status: Open Access ,
Economic analysis of groundwater curtailment in Colorado's Republican River basin: study snapshot
(2025-12) Hill, Rebecca, author; Manning, Dale T., author; Suter, Jordan, author; Vomitadyo, Innocent, author; Colorado Water Center, publisher
Access status: Open Access ,
The current, May 2026
(2026-05) Colorado Water Center, author