Anisotropic leaky-mode modulator for holographic video displays.

Every holographic video display is built on a spatial light modulator, which directs light by diffraction to form points in three-dimensional space. The modulators currently used for holographic video displays are challenging to use for several reasons: they have relatively low bandwidth, high cost, low diffraction angle, poor scalability, and the presence of quantization noise, unwanted diffractive orders and zero-order light. Here we present modulators for holographic video displays based on anisotropic leaky-mode couplers, which have the potential to address all of these challenges. These modulators can be fabricated simply, monolithically and at low cost. Additionally, these modulators are capable of new functionalities, such as wavelength division multiplexing for colour display. We demonstrate three enabling properties of particular interest-polarization rotation, enlarged angular diffraction, and frequency domain colour filtering-and suggest that this technology can be used as a platform for low-cost, high-performance holographic video displays.

Health care costs tied to many issues.

Although, in 1990, the United States spent about $750 billion (12.2 percent of the Gross National Product) on health care, 31-37 million people in this country are uninsured. Another 4 million people are thought to be underinsured. We have one of the highest infant mortality rates among developed industrialized nations and rank 19th in health care and well-being among those nations. Our life expectancy is lower than those of some third-world countries. The United States and South Africa are the only two industrialized nations without a national health care policy. In spite of these statistics, U.S. health care costs continue to rise and, by the year 2000, are expected to reach $1.5 trillion (15 to 17.5 percent of the GNP. Per capita spending on health care will reach $5,515 by the year 2000, compared with $2,425 in 1990 and $1,016 in 1980.

HIV testing of health care workers.

Until recently, nothing much beyond education and the dispensing of condoms was being done to control the spread of AIDS. We have not yet taken sufficient measures to prevent the spread of this disease. Instead, we insist on protecting the privacy of the HIV-positive individual. However, we ignore the right to privacy by mandating testing for syphilis, which is not nearly as serious a disease as AIDS. Now, mandatory testing of health care workers is being proposed more frequently.