2-Properties of light
1. Duality of Light:
● Wave-Particle Duality: Light behaves both as a wave and as a particle.
This dual nature is essential in optical spectroscopy. We must often
switch between considering light as a wave (with properties like
wavelength and frequency) and as photons (the particle aspect).
2. Definition of Light:
● Light can be defined as a self-propagating electromagnetic wave or
as a stream of photons.
● Self-Propagating: This means that light does not need a medium to
travel through; it can propagate (move) on its own, transferring energy
without needing an external push.
3. Example of Non-Self-Propagating Electromagnetic Waves:
● Magnetic Fields: Magnetic fields themselves are not necessarily self-
propagating. A magnetic field generated in a coil, for example, does not
propagate unless it is accompanied by a change in the electric field,
forming a full electromagnetic wave.
4. Electromagnetic Waves in NMR (Nuclear Magnetic Resonance):
● NMR uses radio-frequency coils to detect signals. However, these coils
only generate non-self-propagating waves (just oscillating currents),
meaning they are not continuously generating electromagnetic waves.
● For a wave to be considered light, it must propagate energy from one
point to another, creating a continuous electromagnetic wave.
● NMR is not part of optical spectroscopy because it uses non-self-
propagating waves, unlike light which propagates continuously.
2.1 Energy
1. Properties of Light:
● Wavelength: One of the most important characteristics of light. In optical
research, energy is key. The energy of light is proportional to its
frequency (ν), with the formula E = hν (E is energy, h is Planck's
constant, ν is frequency). If you relate frequency to wavelength, you get
the formula ν = c/λ, where c is the speed of light, and λ is the
wavelength. Therefore, both frequency and wavelength define the energy
of light.
2. Electromagnetic Spectrum (EM Spectrum):
● The EM spectrum describes different types of light energy. It assigns
different energy levels of light specific names, ranging from low to high
frequency.
○ From right to left, energy and frequency increase.
○ Low Frequency Range: Starting at 10^9 Hz, this is mainly radio
1. Duality of Light:
● Wave-Particle Duality: Light behaves both as a wave and as a particle.
This dual nature is essential in optical spectroscopy. We must often
switch between considering light as a wave (with properties like
wavelength and frequency) and as photons (the particle aspect).
2. Definition of Light:
● Light can be defined as a self-propagating electromagnetic wave or
as a stream of photons.
● Self-Propagating: This means that light does not need a medium to
travel through; it can propagate (move) on its own, transferring energy
without needing an external push.
3. Example of Non-Self-Propagating Electromagnetic Waves:
● Magnetic Fields: Magnetic fields themselves are not necessarily self-
propagating. A magnetic field generated in a coil, for example, does not
propagate unless it is accompanied by a change in the electric field,
forming a full electromagnetic wave.
4. Electromagnetic Waves in NMR (Nuclear Magnetic Resonance):
● NMR uses radio-frequency coils to detect signals. However, these coils
only generate non-self-propagating waves (just oscillating currents),
meaning they are not continuously generating electromagnetic waves.
● For a wave to be considered light, it must propagate energy from one
point to another, creating a continuous electromagnetic wave.
● NMR is not part of optical spectroscopy because it uses non-self-
propagating waves, unlike light which propagates continuously.
2.1 Energy
1. Properties of Light:
● Wavelength: One of the most important characteristics of light. In optical
research, energy is key. The energy of light is proportional to its
frequency (ν), with the formula E = hν (E is energy, h is Planck's
constant, ν is frequency). If you relate frequency to wavelength, you get
the formula ν = c/λ, where c is the speed of light, and λ is the
wavelength. Therefore, both frequency and wavelength define the energy
of light.
2. Electromagnetic Spectrum (EM Spectrum):
● The EM spectrum describes different types of light energy. It assigns
different energy levels of light specific names, ranging from low to high
frequency.
○ From right to left, energy and frequency increase.
○ Low Frequency Range: Starting at 10^9 Hz, this is mainly radio
