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Mid-wave infrared liquid crystal shutter for breathalyzer applications

Piecek W., Jaroszewicz L., Miszczyk E., Raszewski Z., Mrukiewicz M., Kula P., Jasek K., Perkowski P., Nowinowski-Kruszelnicki E., Zieliński J., Kędzierski J., Olifierczuk M., Chodorow U., Morawiak P., Mazur R., Kowiorski K., Harmata P., Herman J.

Opto-Electronics Review

2017

Vol. 25, No. 2

103--109

There exists a problem with an in situ diagnostics of contamination of ethyl alcohol in a human being exhaled air. When ethyl alcohol in a mouth blowing (in a gaseous state) exists, the characteristic C-H stretch absorption bands in CH3 and CH2 functional groups in ethanol (CH3CH2OH) appear at a wave length of λ = 3.42 µm. To investigate the presence of ethyl alcohol in exhaled human air, the light beam of λ = 3.42 µm is passing through an air sample. If one alternately measures the intensity of the investigated beam and the reference, a percentage of ethanol in the air sample can be estimated using a sensitive nondispersive infrared (NDIR) system with a stable operating flow mass detector. To eliminate a mechanical chopper and noise generating stepper motors, a photonic chopper as a liquid crystal shutter for λ = 3.42 µm has been designed. For this purpose, an innovative infrared nematic liquid crystal mixture was intentionally prepared. The working mixture was obtained by a selective removal of C-H bonds and its exchange by heavier polar substituents, what ensures a lack of absorption band of C-H bonds. The paper presents theory, concept and final experimental results of the infrared nematic liquid crystals mixture and the liquid crystal shutter for breathalyzer applications.

Refractive index matched half-wave plate with a nematic liquid crystal for three-dimensional laser metrology applications

Piecek W., Jaroszewicz L. R., Miszczyk E., Raszewski Z., Mrukiewicz M., Perkowski P., Nowinowski-Kruszelnicki E., Zieliński J., Olifierczuk M., Kędzierski J., Sun X. W., Garbat K., Kowiorski K., Morawiak P., Mazur R., Tkaczyk J.

Opto-Electronics Review

2016

Vol. 24, No. 4

169--182

There exists a need in a quality and accuracy of a three-dimensional laser metrology operating in numerically controlled automatic machines. For this purpose, one sends three laser beams mutually perpendicular. These three beams of the wavelength λ = 0.6328 μm are generated by the same laser and are directed along three independent, orthogonal, mutually perpendicular, optical paths with a given light polarization plain. Using these beams, constituting the frame of coordinates, three independent laser rangefinders are able to determine spatial coordinates of a working tool or a work piece. To form these optical pulses, a special refractive index matched Half-Wave Plate with nematic Liquid Crystal (LCHWP) was applied. The presented half-wave plate is based on a single Twisted Nematic (TN) cell (with the twist angle φ = π/2) of a rather high cell gap d ~15 μm filled with a newly developed High-Birefringence Nematic Liquid Crystal Mixture (HBLCM) of optical anisotropy as high as ∆n ~0.40 at λ = 0.6328 μm, where the Mauguin limit above 5.00 ~ ∆nd >> λ/2 = 0.32 is fulfilled.

Transparent laser damage resistant nematic liquid crystal cell “LCNP3”

Raszewski Z., Piecek W., Jaroszewicz L., Dąbrowski R., Nowinowski-Kruszelnicki E., Soms L., Olifierczuk M., Kędzierski J., Morawiak P., Mazur R., Miszczyk E., Mrukiewicz M., Kowiorski K.

Opto-Electronics Review

2014

Vol. 22, No. 3

196-200

There exists the problem in diagnostics of dense plasma (so-called Thomson diagnostics). For this purpose the plasma is illuminated by series of high energy laser pulses. The energy of each separate pulse is as large as 3 J, so it is impossible to generate a burst of such pulses by a single laser. In this situation, the pulses are generated by several independent lasers operating sequentially, and these pulses are to be directed along the same optical path. To form an optical path with ʎ = 1.064 μm and absolute value of the laser pulse energy of 3 J, a special refractive index matched twisted Nematic Liquid Crystal Cell of type LCNP3, with switching on time ƮON smaller than 3 μs was applied.