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C. W. Huck
some other techniques, e.g., fluorescence, NIR spectroscopy is superior in chemical specificity and applicability to a broad range of sample types. The most recent
years have led to emerging new class of spectrometers, miniaturized NIR devices
that can reach weigh of sub-100 g, and ultra-miniaturized sensors that are compact
enough to be built-in directly into a smartphone device. Several ultra-miniaturized
NIR spectrometers appeared in the past decade. This new-generation devices are USB
powered or operate under own power source (usually Li-ion battery) and are intended
for easy use. Such spectrometers often come with software designed for easy and
rapid operation by non-expert personnel. Moreover, spectra measurement by these
spectrometers is often much more rapid than in the case of benchtop instrument.
Sensor miniaturization has a critical importance for several practical applications
[8]. The first breakthrough to practical availability of handheld NIR instruments
was micro-optoelectronic-mechanical systems (MEMS) and miniature diode-array
detectors (DAD). The first handheld, all-in-one portable (1.5 kg) NIR spectrometer
was introduced commercially by Polychromix 2006, and the instrument is nowadays
known as microPHAZIR by Thermo Fischer Scientific. This design was engineered
with MEMS wavelength selector and tungsten light source. The next noteworthy step
into further miniaturization was made in 2012 by JDS Uniphase (currently ViaviSolutions, Milpits, CA, USA) with the MicroNIR instrument. A very compact size was
achieved through using a linear variable filter (LVF) element for the wavelength selection together with a 128-pixel InGaAs DAD. This multi-channel design also enabled
very quick scanning, with less than 1 s required to measure the entire spectrum [9,
10]. In 2016, Texas Instrument presented an optical engine with the dimensions of 33
× 29 × 10 mm in their DLP NIRscan product. It incorporated a digital micromirror
device (DMD) principle with diffraction grating system. The current advances in
the miniature technology make it feasible to fully integrate a NIR spectrometer into
smartphone in the near future (Fig. 8.5) [11].
For most practical applications that adopt portable spectrometers of all kinds, a
successful design should possibly achieve the following characteristics; (i) handheld
format/high level of miniaturization, (ii) ruggedness (e.g., no moving parts, resilience
against external conditions, temperature, etc.), (iii) affordability, and (iv) straightforward applicability in routine analysis (e.g., rapid measurement, easy handling
by non-expert personnel). It may be safely stated that, in most points, NIR spectrometers are particularly suitable for miniaturization. However, as it is known, NIR
spectral analysis is not straightforward and typically requires supervision by expert
personnel. Significant efforts are being directed nowadays to make NIR analysis by
handheld devices more accessible for non-trained operators. Some of the proposed
solutions, e.g., blackbox operation, ‘factory’ chemometric calibration procedures,
cloud computing, still leave much to be desired and are discussed by the NIR
spectroscopic community [12].
Nonetheless, advancements made over the past decade enabled spectroscopic
measurements in previously unattainable scenarios and create new opportunities for
innovative applications in wide field of science and industry. Therefore, portable
instrumentation forms a significant breakthrough in NIR spectroscopy and may
become the key advancement for widespread of this technique in forthcoming time.
C. W. Huck
some other techniques, e.g., fluorescence, NIR spectroscopy is superior in chemical specificity and applicability to a broad range of sample types. The most recent
years have led to emerging new class of spectrometers, miniaturized NIR devices
that can reach weigh of sub-100 g, and ultra-miniaturized sensors that are compact
enough to be built-in directly into a smartphone device. Several ultra-miniaturized
NIR spectrometers appeared in the past decade. This new-generation devices are USB
powered or operate under own power source (usually Li-ion battery) and are intended
for easy use. Such spectrometers often come with software designed for easy and
rapid operation by non-expert personnel. Moreover, spectra measurement by these
spectrometers is often much more rapid than in the case of benchtop instrument.
Sensor miniaturization has a critical importance for several practical applications
[8]. The first breakthrough to practical availability of handheld NIR instruments
was micro-optoelectronic-mechanical systems (MEMS) and miniature diode-array
detectors (DAD). The first handheld, all-in-one portable (1.5 kg) NIR spectrometer
was introduced commercially by Polychromix 2006, and the instrument is nowadays
known as microPHAZIR by Thermo Fischer Scientific. This design was engineered
with MEMS wavelength selector and tungsten light source. The next noteworthy step
into further miniaturization was made in 2012 by JDS Uniphase (currently ViaviSolutions, Milpits, CA, USA) with the MicroNIR instrument. A very compact size was
achieved through using a linear variable filter (LVF) element for the wavelength selection together with a 128-pixel InGaAs DAD. This multi-channel design also enabled
very quick scanning, with less than 1 s required to measure the entire spectrum [9,
10]. In 2016, Texas Instrument presented an optical engine with the dimensions of 33
× 29 × 10 mm in their DLP NIRscan product. It incorporated a digital micromirror
device (DMD) principle with diffraction grating system. The current advances in
the miniature technology make it feasible to fully integrate a NIR spectrometer into
smartphone in the near future (Fig. 8.5) [11].
For most practical applications that adopt portable spectrometers of all kinds, a
successful design should possibly achieve the following characteristics; (i) handheld
format/high level of miniaturization, (ii) ruggedness (e.g., no moving parts, resilience
against external conditions, temperature, etc.), (iii) affordability, and (iv) straightforward applicability in routine analysis (e.g., rapid measurement, easy handling
by non-expert personnel). It may be safely stated that, in most points, NIR spectrometers are particularly suitable for miniaturization. However, as it is known, NIR
spectral analysis is not straightforward and typically requires supervision by expert
personnel. Significant efforts are being directed nowadays to make NIR analysis by
handheld devices more accessible for non-trained operators. Some of the proposed
solutions, e.g., blackbox operation, ‘factory’ chemometric calibration procedures,
cloud computing, still leave much to be desired and are discussed by the NIR
spectroscopic community [12].
Nonetheless, advancements made over the past decade enabled spectroscopic
measurements in previously unattainable scenarios and create new opportunities for
innovative applications in wide field of science and industry. Therefore, portable
instrumentation forms a significant breakthrough in NIR spectroscopy and may
become the key advancement for widespread of this technique in forthcoming time.