Production and evaluation of silicon immersion gratings for infrared astronomy.

Immersion gratings, diffraction gratings where the incident radiation strikes the grooves while immersed in a dielectric medium, offer significant compactness and performance advantages over front-surface gratings. These advantages become particularly large for high-resolution spectroscopy in the near-IR. The production and evaluation of immersion gratings produced by fabricating grooves in silicon substrates using photolithographic patterning and anisotropic etching is described. The gratings produced under this program accommodate beams up to 25 mm in diameter (grating areas to 55 mm x 75 mm). Several devices are complete with appropriate reflective and antireflection coatings. All gratings were tested as front-surface devices as well as immersed gratings. The results of the testing show that the echelles behave according to the predictions of the scalar efficiency model and that tests done on front surfaces are in good agreement with tests done in immersion. The relative efficiencies range from 59% to 75% at 632.8 nm. Tests of fully completed devices in immersion show that the gratings have reached the level where they compete with and, in some cases, exceed the performance of commercially available conventional diffraction gratings (relative efficiencies up to 71%). Several diffraction gratings on silicon substrates up to 75 mm in diameter having been produced, the current state of the silicon grating technology is evaluated.

Fabrication and testing of chemically micromachined silicon echelle gratings.

We have fabricated large, coarsely ruled, echelle patterns on silicon wafers by using photolithography and chemical-etching techniques. The grating patterns consist of 142-microm-wide, V-shaped grooves with an opening angle of 70.6 degrees, blazed at 54.7 degrees. We present a detailed description of our grating-fabrication techniques and the results of extensive testing. We have measured peak diffraction efficiencies of 70% at lambda = 632.8 nm and conclude that the gratings produced by our method are of sufficient quality for use in high-resolution spectrographs in the visible and near IR (lambda approximately = 500-5000 nm).

Fabrication and evaluation of an etched infrared diffraction grating.

We evaluated the optical performance of an IR echelle grating produced on a silicon wafer with anisotropic etching techniques. We measured the diffraction efficiency of a sample with a 55° blaze angle and 25-µm groove spacing. We also calculated the efficiency for typical triangular and trapezoidal groove profiles of etched gratings. The diffraction efficiency for unpolarized light can be approximately as high as the efficiency of right-angle groove gratings. The great potential of the etched silicon grating lies in its ease of fabrication, its excellent surface quality, and the high reproducibility of the production process. Compact high-resolution diffraction gratings can be produced by etching the grating pattern into the rear side of a transparent prism. When used in internal reflection, this increases the resolving power of the grating by a factor equal to the refractive index of the prism over a front surface grating of the same length.

Managing occupational stress associated with HIV infection. Self-care and self-management skills.

There is a crisis in health care that has to do with the ability of health-care workers to provide the long-term care and help for AIDS patients. Although more severe, it is just an extreme form of the denial among health care professionals of their own needs, and lack of ability to manage stress. The situation also reflects absence of explicit concern in health settings for creating environments that are healthy for staff. This paper has suggested some of the forms that a comprehensive response to this problem can take.

Holistic physicians and family practitioners: similarities, differences and implications for health policy.

Although loosely defined, holistic or alternative medicine has been viewed by most observers as fundamentally at odds with mainstream biomedical approaches. Convergence or integration of the two are seen as highly unlikely. We attempt to assess the potential for such integration empirically through a survey of physicians, members of the American Holistic Medical Association (N = 340) and a comparison group of family practitioners (N = 142). Although social origins of the two groups are similar, they differ in their completion of residency training and a variety of practice characteristics. While the groups differ in the predicted directions in their evaluation and utilization of holistic techniques and in their attitudes toward the nature of medical practice, there is a good deal of overlap. Personal experiences, especially those in the area of religion/spirituality and psychotherapy differ sharply between the groups. Policy concerned with fostering cooperation or convergence between holistic and mainstream medicine should differentiate between clinical attitudes and behaviors (which appear to be more compatible than has been suggested), and the personal world views of physicians (which appear to be much further apart).

Holistic physicians and family practitioners: an empirical comparison.

We report on a survey of 340 self-identified, holistic physicians (members of the American Holistic Medical Association) and a group of 142 California family practitioners (FPs). The groups are quite similar in age, gender, socioeconomic origin, and marital status. Holistic physicians are more likely to be from rural origins, not board certified, in private practice, see fewer patients, and use hospitals less. Holistic physicians also evaluate and utilize a number of "holistic" medical techniques and interactional styles with patients quite differently than FPs. In addition, the two groups are differentiated by the importance they attribute to religious and/or spiritual factors, as well as their own experiences in psychotherapeutic situations, that influence their views of health, illness, and healing.

The organization of treatment on a short-term psychiatric ward.

While the medical origin of psychiatric treatment has led to a tendency for discussions of treatment to dwell mainly on what is wrong with the psyche of patients, the treatment process of a residential facility consists of interaction between patients and a variety of staff members. It is a social process, and to understand fully what is going on, one might ask not only who is doing and saying what to whom, but who expects what, and how do each of the participants interpret what is going on. In observing the treatment process in a short-term psychiatric ward of a community mental health center, I saw the interaction of at least two different concepts and styles of treatment--the traditional medical model, and another model based on mobilizing social support. I found that my sociological perspective was useful in looking at the organization of the ward, at the two models of treatment--their interaction, their support of each other, and their occasional conflict, and at the nature of the patient role and the treatment process.