Spectrographs for UV, NIR & SWIR

Luminescence

Luminescence spectroscopy is used for a large variety of applications including for example the study of metal complexes, organic LEDs (OLEDs), quantum dots, cell dynamics, stand-off detection of chemical compounds (e.g. explosives) or scintillators properties measurement. Key techniques include:

• Fluorescence
• Photoluminescence
• Cathodoluminescence
• Chemiluminescence

Further Reading
App Note: Determination of Fluorescence Lifetimes using TRLFS
App Note: Characterization of Single Quantum Wires 
App Note: Magneto-Photoluminence in Si Nanocrystals

Absorption / Transmission / Reflection

Ultraviolet Visible Near-Infra red (UV-Vis-NIR) spectroscopy is useful to characterise the absorption, transmission, and reflectivity of a variety of materials such as pigments, biological, coatings, windows, filters, or analyse the dynamics of chemical reactions. Variations of these spectroscopy techniques include:

• Transient absorption (pump/probe)
• Diffuse Reflectance

Further Reading
Tech Note: Intro to Absorption, Transmission & Reflection
App Note: Spectral Response of Glucose

OES and LIBS

Optical Emission Spectroscopy (OES) is a fundamental, non-invasive diagnostic technique for a wide range of plasma, and can provide information such as composition and species temperature and energy distribution.

Laser-induced breakdown spectroscopy (LIBS) is used to determine the elemental composition of various solids, liquids and gases. A high power laser pulse is focused on to a sample to create a plasma. Emission from the atoms and ions in the plasma is collected and analysed by a spectrograph and gated detector to determine the elemental composition or the elemental concentrations in the sample.

Further Reading
Case Study: Automated 2D elemental mapping by LIBS
Case Study: Stand-off LIBS
Webinar: Basic Principles of LIBS

Microspectroscopy

Micro-spectroscopy covers a very wide range of spectroscopy modalities with the common character that the spectroscopic measurement is made on the microscopic scale. Andor spectroscopy systems are routinely used for Raman-based techniques including:

• Micro- Raman and Fluorescence/Photoluminescence
• Diffuse Scattering micro-spectroscopy
• Multiphoton micro-spectroscopy

Further Reading
Tech Note: Modular Solutions for Micro-Spectroscopy
App Note: Micro-Spectroscopy as a Diagnostic Aid to Skin Cancers

Non-Linear Spectroscopy

Non-linear (NL) spectroscopy encompasses a number of optical techniques that can be used to study for example interfacial and surface processes, ultrafast dynamic processes (pump-probe technique), light transport or assist in the understanding of nanoparticles/nanostructures unique optical properties. Key techniques include:

• Second harmonic generation (SHG) spectroscopy
• Sum-frequency generation (SFG) spectroscopy
• Pump-probe transient absorption
• Coherent Anti-Stokes Raman Scattering (CARS)

Further Reading
App Note: Spectral Characterization of Quantum Light
App Note: Nearfield Spectroscopy of a ZnO Thin Film

Material Science

Optical spectroscopy can provide analytical information on materials from the micro to the nano-scale, through a number of techniques with a large range of sensitivity, resolution and flexibility requirements. Examples include:

• Quantum dots
• Carbon nanotubes
• Nanowires
• Organic LEDs (OLEDs)
• Thin films
• Scintillators
• Powder/explosives

Further Reading
App Note: Chemical Analysis of Nanostructures by TERS
App Note: Nearfield Spectroscopy of a ZnO Thin Film

Chemical Processes

Optical spectroscopy can be used to non-invasively study the changes in the composition of chemical(s) or material(s).

Chemical reaction products or transient behaviours can be probed by Andor Spectroscopy systems through a variety of techniques based on Raman, transient absorption / pump-probe or fluorescence.

Further Reading
App Note: Quantitative Monitoring of Biphasic Reactions 
App Note: Reaction Monitoring using UV-Resonance Raman
App Note: Reaction monitoring using SWIR Raman Spectroscopy

Life Science - Biomedical

Optical spectroscopy can provide very specific analytical information in a non-invasive matter for a range of bio-samples, often as a complement to microscopy imaging (micro-spectroscopy) or visual inspection.

Field of applications include for example cancer cell in vivo and ex vivo screening and cancer diagnostics, non-invasive monitoring of patient bio-parameters or cell sorting.

Further Reading
App Note: Identification of Lung Cancers
App Note: Diagnosis of skin tumors during micrographic surgery
App Note: Optical Spectroscopy in Biomedical research

Plasma Studies

Plasmas can be artificially produced by different means (e.g. laser ablation, coupling of capacitive / inductive power source to ionised gas). The understanding of their properties and dynamics is relevant to a number fields such as fusion, thin films deposition, micro-electronics, material characterization, display systems, surface treatment, fundamental physics, environmental & health.

Gated detectors can be used to determine optical parameters from which fundamental plasma properties can be derived. Accurate nanosecond-scale gating of image intensifier-based detectors can be used to sample plasma dynamics, or to isolate the useful plasma information generated by pulsed lasers.

Further Reading
App Note: PLIF as a Plasma Diagnostic
App Note: Broadband Cavity-enhanced Absorption Spectroscopy
App Note: Thomson Scattering