# Helix-Free Ferroelectric Liquid Crystals: Electro Optics and Possible Applications
## 7 Conclusions  
Based on our research results, we considered in detail the physical properties, light modulation characteristics, and possible applications of novel helix-free FLC developed and fabricated at the  
Figure 15: Illustration of the operation of an experimental sample of a despeckler using the novel helix-free FLC: (**a**) Oscillograms of the control voltage (zero level—digit 3) and phase delay modulation (zero level—digit 1); value of a low-frequency signal (meander) 2 kHz and amplitude \(\pm\)50 V; frequency of the modulating signal is 7 kHz and amplitude \(\pm\)15 V; electric field strength is 3.25 V/\(\upmu\)m; (**b**) Radiation intensity distribution in the cross section of a laser beam transmitted through the electro-optical despeckler sample when the control voltage is zero; contrast of the speckle pattern \(C_{0}=0.82\); (**c**) Radiation intensity distribution in the cross section of a laser beam in the presence of the control voltage; contrast of the speckle pattern \(C_{1}=0.07\). The thickness of the FLC cell is 20 \(\upmu\)m. The wavelength of the laser radiation is 0.65 \(\upmu\)m.  
Lebedev Physical Institute, Moscow. They are distinguished by the spatially periodic deformation of smectic layers, a small value of spontaneous polarization, rather high viscosity, and the soliton mechanism of FLC director reorientation upon transition to the Maxwellian mechanism of energy dissipation.  
For FLC with a viscosity in the range from 0.15 to 1.0 P, the frequency and field dependences of the electro-optical response time were studied under modulation of light transmission, light scattering, and light phase delay.  
When modulating the light transmission in an electric field of the order of 1 V/\(\upmu\)m (at the control voltage of \(\pm\)1.5 V), the smallest response time (25 \(\upmu\)s) and the largest modulation frequency interval (7 kHz, including 6 kHz for hysteretic-free modulation with continuous grayscale) were realized experimentally for the first time.  
A theoretical model was proposed that described satisfactorily the deformation of smectic layers in the absence of the external electric field and the soliton mechanism of FLC director reorientation under an alternating electric field.  
In certain compositions of the new FLC, intensive light scattering on transient domains was realized, including the discovery for the first time of bistable scattering with a memory time that can exceed the optical switching time (tens of microseconds) by 6 orders of magnitude (up to tens of seconds).  
Initiated by the short-time switching on of light scattering, the spatially inhomogeneous phase light modulation due to random small-scale gradients of the FLC refractive index was studied. This modulation is capable of destroying the phase relations in a laser beam and of suppressing the speckle noise in images formed by the beam. Based on this, experimental samples of simple and effective electro-optical despecklers were studied for the first time.  
Possible applications of the novel helix-free FLC are the fastest display devices (including displays using FLCoS, 3D, and FSC technologies), spatial light modulators, light-scattering polarizer-free modulators (including infrared devices and optical-state-memorizing ones), energetically effective screens of electronics books, 3D visualizers (volumetric screens) of volumetric displays, coding-decoding devices, etc.