ABSTRACT
We present what we believe to be the first implementation of a Fabry-Perot (FP) etalon using polymer cholesteric liquid-crystal mirrors. These polymer mirrors have each been fabricated onto a single substrate, which allows the FP cavity spacing to be only a few micrometers wide. For the experimental results presented, cavity lengths of 13.8 and 7.6 microm yield near-infrared free spectral ranges of 24.8 and 45.6 nm, respectively. The measured finesse of 14.31 is approaching the limitation imposed by the reflectivity of the mirrors.
ABSTRACT
We report what is to our knowledge the first implementation of a broadband analog intensity modulator composed of two chiral smectic liquid-crystal half-wave retarders. A reflection-mode intensity modulator employing a single active device has also demonstrated achromatic transmission. A quantitative theory for chromatic compensation is presented. By optimum selection of liquid-crystal retardance and orientation, intensity transmission is uniform throughout the visible. The chiral smectic liquid-crystal devices used in the implementation are capable of switching in less than 20 micros.
ABSTRACT
A homogeneously aligned smectic A* liquid-crystal quarter-wave retarder is used to produce analog complex-amplitude modulation of light through the electroclinic effect. The device consists of a reflection-mode polarization rotative phase shifter enhanced by an asymmetric resonator. With an entrance mirror reflectivity of 70%, an analog modulation of 65% of a fringe was observed. The 10-90% response time of the liquid crystal was measured to be 25 micros at 25 degrees C.
ABSTRACT
The use of 2-kHz 64 × 64 very-large-scale integrated circuit/ferroelectric-liquid-crystal electrically addressed spatial light modulators as the input and filter planes of a VanderLugt-type optical correlator is discussed. Liquid-crystal layer thickness variations that are present in the devices are analyzed, and the effects on correlator performance are investigated through computer simulations. Experimental results from the very-large-scale-integrated/ferroelectric-liquid-crystal optical-correlator system are presented and are consistent with the level of performance predicted by the simulations.
ABSTRACT
A ferroelectric liquid-crystal (FLC) color filter is described and experimentally demonstrated. The device consists of three polarizers and five smectic C* FLC cells. With the application of an appropriate electric field to each FLC cell, five outputs are observed. These consist of the three primary colors (red, green, and blue) along with white and black. With the rapid addressing speed of the FLC's, the FLC color filter can be used for color display applications, such as backlighting FLC television.
ABSTRACT
Eighty women receiving spinal anesthesia for postpartum tubal ligation were entered into a double-blind, randomized protocol studying the effects of epinephrine on intrathecal fentanyl-induced postoperative analgesia. All patients received 70 mg hyperbaric lidocaine with either 0.2 mg epinephrine (LE), 10 micrograms fentanyl (LF), epinephrine and fentanyl (LFE), or 0.4 ml saline (L). Onset and regression of anesthesia, degree of intraoperative comfort, incidence of pruritus, and extent of postoperative analgesia were evaluated. The simultaneous administration of epinephrine and fentanyl prolonged the duration of complete analgesia (137 +/- 47 min (LFE); 76 +/- 32 min (LE); 85 +/- 44 min (LF); 65 +/- 36 min (L)) and the duration of effective analgesia (562 +/- 504 min (LFE); 227 +/- 201 min (LE); 203 +/- 178 min (LF); 198 +/- 342 min (L)). Administration of epinephrine decreased the incidence of pruritus associated with intrathecal fentanyl (1/18 (LFE); 1/21 (LE); 8/19 (LF); 2/19 (L)).
Subject(s)
Anesthesia, Spinal , Epinephrine/pharmacology , Fentanyl , Pain, Postoperative/prevention & control , Postpartum Period , Sterilization, Tubal , Adult , Double-Blind Method , Epinephrine/administration & dosage , Female , Humans , Injections, Spinal , Lidocaine/administration & dosage , Lidocaine/pharmacology , Randomized Controlled Trials as TopicABSTRACT
A new continuously tunable color filter, which uses smectic A(*) liquid-crystal half-wave plates, is described and experimentally demonstrated. Multiple-stage Lyot filters with broad tunability and high finesse can be constructed with this design. The transmission characteristics of a single-stage filter, which is continuously tuned over 115 nm of the visible spectrum, are presented. Experimental results are compared with computer simulations, and they show excellent agreement. The advantages of the smectic A(*) liquid-crystal tunable filter over existing filter structures include low switching voltages (+/-30 V), rapid tunability (10 MHz), potentially high transmission, wide field of view, and large aperture.
ABSTRACT
A new discrete-channel tunable Lyot filter that uses ferroelectric liquid-crystal (FLC) smectic C* wave plates is described and demonstrated. The device is tuned by changing the retardation of each birefringent element. This is achieved by electrically rotating the FLC wave plates in each stage by 45 degrees , which effectively changes the design wavelength of the Lyot filter. The transmission characteristics of such a device are demonstrated in a three-stage filter and show good agreement with theory. Advantages of the FLC tunable filter over existing filter structures include low switching voltages (+/-10 V), rapid tunability (~100 kHz), potentially high transmission and wide field of view, and large entrance aperture.
