Hannah Wolfe
Media Art & Technology

Arts and Research
How particles, waves and frequencies are measured and are used to measure in research at UCSB.
The Bazan research group designs molecular structures that absorb light and release different light or generating electricity though electron-hole pairs. These structures can be used designed to be used as light sensors by absorbing one kind of light and releasing another, or as solar cells, absorbing light and releasing electricity. Frequency, waves, and particles are an important part of their research because light is considered both a particle and a wave.

The Hansma Lab introduced the tapping mode in fluids to atomic force microscopy. The sample oscillates up and down, and at the apex of the oscillation is tapped. The Hansma Lab developed smaller cantilevers, which can be used for biological samples which require higher resonant frequencies to have a higher scanning speed. The atomic force microscope's cantilever vibrates at a certain frequency, the farther the distance is from the the surface the higher the frequency is. The AFM adjusts the height of the cantilever so it stays at the same frequency. The movement of cantilever is detected by a laser beam, which is reflected into a photodetector in the microscope. The vibration frequency and laser are used to measure the surface height.
Particles are simulated through research in the CASL lab where they build simulations of nanofluidics, water and smoke. The role of particles in the research is that they are being simulated.
The Sherwin research group works with the Free Electron Laser. The free electron laser has an electrostatic accelerator, a particle accelerator, that accelerates the electrons. They use electrostatic field to propel charged particles into well-defined beams. Similar to a Van de Graff generator or cathode ray tube, it uses an electro static field to accelerate the particles. The beam gets sent into the resonating cavity where it gets wiggled back and forth by magnets so that it emits light. The light bounces back and forth between two mirrors causing them to bunch up and work coherently. One mirror has a hole where some light comes out. One research path that came out of the lab looks at how the FEL laser's terahertz radiation and a visible laser are shined on different materials effects the light released from the material. This animation shows how when terahertz radiation and near infrared radiation is shined on a quantum well that the light emitted has sidebands because the electron removed is attracted to the hole that it leaves and repeatedly collides with it. Sidebands are other frequencies of light that are at a regular interval from the main frequency.
( Experimental observation of electron–hole recollisions )
( Free Electron Laser )
The Fygenson research group looked at DNA-Stabilized Fluorescent Silver, and how it becomes more excitable by UV light. This fluorescence can be used for checking to tag DNA. UV light is electromagnetic radiation with a wavelength shorter then visible light but longer than x-rays. From measuring eletrcophroretic mobility they determined there are 2 kinds of emitters, one that emits green light and another that emits red light.
( Distinct Conformations of DNA-Stabilized Fluorescent Silver Nanoclusters Revealed by Electrophoretic Mobility and Diffusivity Measurements )
For the Center for Control Dynamical-Systems and Computation they use infrared sensors, GPS, and radio waves as a way to track the agents and communicate with them. Infrared sensors uses electromagnetic radiation with wavelengths longer than visible light from 700 nm to 1 mm. Radio waves correspond to wavelengths from 1mm to 100 km. Here they use electromagnetic radiation to track the agents and to allow the agent to know where it is. By tracking the agent, it's path efficiency can be evaluated.

The Kosik Group uses an Ion Torrent Ion Proton sequencer to sequence DNA. This uses negatively charged ions released from the DNA to sequence DNA. The DNA sample is split up into many smaller samples so that the process can be run in parallel. A DNA segment is then replicated and blasted with nucleotides that when they join to the DNA a hydrogen ion is released. A semiconductor chip is used with 660 million sensors is used to monitor the acidity of the solution.
( Ion Proton Sequencer )

The Liebling Lab uses bright field microscopy, and UV light to look at genetically engineered zebra fish that have green fluorescent proteins in their heart cells. Bright field microscopy uses white light to illuminate the sample so it can be seen. Fluorescence is the emission of light by a substance that has absorbed light, typically the emitted light has a longer wavelength and lower energy than the absorbed radiation. Here fluorescence is being used as a way to view what they are measuring.
Waves and frequencies are an important part of the Schuller lab's research on Dielectric Resonator Antennas and Molecular Antennas. The dielectric resonator antenna releases microwave frequencies. In a dielectric resonator antenna, radio waves are introduced into the resonator material, bouncing back and forth creating standing waves. The walls allow some radio power to escape into space. Molecular Antennas are layered materials that can be used for solar cells and molecular sensors. Dipole orientations cause distinct antenna-like radiation patterns. These patterns can be looked at experimentally using back photo plane imaging focused through a slit, where every point in the image plane corresponds to a distinct angle of emission.
( Orientation of luminescent excitons in layered nanomaterials )

The Lubin Lab worked on the instrument on the Planck satellite that measures cosmic microwave background radiation. Cosmic microwave background radiation peaks at 160.2 GHz in the microwave range of frequencies. The instrument is made out of an array of low and high frequency instruments. LFI (Low Frequency Instrument) is an array of 22 microwave radiometers. a combination of ultralow-noise amplifiers and high-electron-mobility transistors are cryogenically cooled to 20 K to measure the signals. It has a lower power consumption across frequencies and have little noise in the 30-70 GHz range which is being measured. HFI (High Frequency Instrument) is an array of 48 bolometers. A bolometer detects infrared and mm wave light by detecting heat. The light absorbed on the surface of the bolometer, a spiderweb like structure, heats it, and the heat is measured by a thermistor. The spiderweb is designed so that long-wavelength thermal radiation are absorbed, but high-energy cosmic rays pass through. The web design makes them lighter and less sensitive to vibrations. The spiderweb is made out of 1 micron think silicon nitride coated with gold. Some of them are only sensitive to a single polarization of incoming radiation. The detectors operate at the cryogenic temperature of 0.1 K, obtained using a cryochain of absorption, mechanical and dilution coolers.
( Planck Satellite )
( Planck - LFI )
( Planck - HFI )