Structured light fields are highly susceptible to various aberrations, and so there is a large amount of research into the effects of turbulence on these fields and into methods of mitigating these effects. Much of this research is performed using simulated turbulence. Although simulated turbulence is useful, it is not always sufficient and sometimes a turbulent free-space link is required. Setting up such a link requires several nuanced considerations and potentially time-consuming steps. Tailored for beginners, in this tutorial-style paper we document our practical experience in building structured light free-space links.
Digital Micromirror Devices (DMDs) can be used as alternatives to liquid crystal spatial light modulators, and due to their high speed and resolution, relatively low cost as well as wavelength and polarization invariance, are gaining popularity in the structured light community. We briefly summarise several practical considerations when using DMDs in structured light, explain how to generate holograms to modulate the amplitude and phase of an incident laser beam, as well as how to generate vector modes with spatially varying polarisation.
Visible Light Communications (VLC) as well as Mode Division Multiplexing is a research area that is currently receiving significant interest which is beginning to migrate from proof-of-principle demonstrations towards optimized engineering. The ability to easily transmit and receive arbitrarily encoded and modulated optical signals is critical to prototyping in a lab environment. Software defined radios enable cost-effective development and testing of almost any coding scheme and modulation format with a significant bandwidth, if required. We present our experiences with using software defined radios and other platforms to drive LEDs and laser diodes and subsequently receive the transmitted signals.
Structured laser beams have numerous applications, for example mode division multiplexing, optical tweezers and even astronomy. Spatial Light Modulators are typically used to display digital holograms, however they have a low refresh rate, only work with a single polarisation and operate on a limited range of wavelengths. Digital Micro-mirror Devices are able to spatially modify the amplitude of incident light as opposed the the phase and are increasing in popularity due to their high refresh rate, polarisation and wavelength invariance and they are able to work as digital holograms with the right encoding. We describe how these devices may be used in a laboratory environment for modal decomposition as well as some of their disadvantages. We describe a method to accurately measure the flatness of a DMD, which is one of the major issues with the devices.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.