described by Dutch physicist frits
Zernike in 1934.
It is a type of light microscopy.
It is a contrast enhancing optical technique
that produces high contrast images of
Specimen- unstained and alive.
RING : is between condenser and
PHASE RING : is between objective lens and
SPL PROPERTY : both the rings allow partial
light to pass through it and the rest is
Basic mechanism is interference of light
Interaction of two light waves which leads to
the formation of resultant wave.
TYPES OF INTERFERENCE:
passes through the condenser via
After reaching the specimen plate two types
of beams are formed.
IF THERE IS NO SPECIMEN IN LENS:
1.Surrounding wave (S)
2.particle wave (p)
LENS CONTAINS SAMPLE:
Light beam gets diffracted because of
different density at different regions of
1.surrounding wave (S)
2.diffaracted wave (D)
Either constructive interference or
destructive interference may occur.
phase contrast produces
Thus, the image of the specimen obtained is
Inner region of the sample – darker
Outer region of the sample– bright
Surrounding lens – opaque
phase contrast microscopy produces
Thus, the image obtained is
Inner region of the sample – bright
Outer region of the sample– darker
Surrounding lens – opaque
an one of the light microscope.
It refers to any microscope
that uses fluorescence to
generate an image.
It produces 3d image.
The technique is used to
study specimens, which
can be made to fluorescence.
phenomenon that takes place
when a substance absorbs
light at a given wavelength
and emits light at another
Fluorescence occurs as an
electron, which has been
excited to a higher, and more
unstable energy state,
relaxes to its ground state
and gives off a photon of
sample to be analyzed Is placed on a
lens. And the sample is coated with a
The light is illuminated through the lens with
the higher energy source. The illumination
light is absorbed by the fluorophores.
The sample causes them to emit a longer
lower energy wavelength light.
This fluorescent light can be separated from
the surrounding radiation with filters.
The light from the light
source is passed through
the excitation filter.
The specific wavelength of
light is passed through the
sample via dichronic filter.
The objective lens focuses
the light to the specimen.
The light emitted from the
specimen is filtered by
structural components of small
specimens, such as cells.
Conducting viability studies on cell
populations (are they alive or dead).
Imaging the genetic material within a cell
(DNA and RNA).
Viewing specific cells within a larger
population with techniques such as FISH.
To differentiate different type of cell.