NT-MDT Solver SNOM User manual
Read me First!
Observe safety measures for operation with devices containing sources of laser radiation.
Do not stare into the beam. A label warning about the presence of laser radiation is
attached to the laser sources (Fig. 1).
Fig. 1
Before you start working with the instrument, get acquainted with the basic safety
measures and the operation conditions for the instrument!
If you are a beginner in scanning probe microscopy, we recommend you to familiarize with
basic SPM techniques. “Fundamentals of Scanning Probe Microscopy” by V.L. Mironov
gives a good introduction to the subject. This book is available free of charge at
https://www.ntmdt-si.com/customer-support/manuals/textbook.
Feedback
Should you have any questions, which are not explained in the manuals, please contact the
give you comprehensive answers. Alternatively, you can contact our staff on-line using
the ask-on-line service (http://online.ntmdt-si.com/online).
User’s documentation set
The following manuals are included into the user’s documentation set:
-Instruction Manual – is the guidance on preparation of the instrument and other
equipment for operation on various techniques of Scanning Probe Microscopy. The
contents of the user’s documentation set may differ depending on the delivery set of the
instrument.
-SPM Software Reference Manual – is the description of the control program
interface functions, all commands and functions of the menu and, also a description of
the Image Analysis module and the Macro Language “Nova PowerScript”.
-Control Electronics. Reference Manual – is the guide to SPM controller,
Thermocontroller and Signal Access module.
Some equipment, which is described in the manuals, may not be included into your
delivery set. Read the specification of your contract for more information.
The manuals are updated regularly. Their latest versions can be found in the site of the
company (http://www.ntmdt-si.com/support).
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
Solver SNOM. Scanning Near-Field Optical
Microscope. Instruction Manual
Table of Contents
1. BASIC INFORMATION.........................................................................................................................5
1.1. PURPOSE OF THE SOLVER SNOM..................................................................................................... 5
1.2. DESCRIPTION OF MAIN COMPONENTS .............................................................................................. 5
1.2.1. Inverted Optical Microscope ......................................................................................... 6
1.2.2. XY Scanning Stage.........................................................................................................7
1.2.3. Z-scanner of the objective..............................................................................................8
1.2.4. SNOM Measuring Head.................................................................................................9
1.2.5. Optical Fiber Probe.....................................................................................................12
1.2.6. Photomultiplier Modules.............................................................................................. 13
1.2.7. Laser Module...............................................................................................................14
1.2.8. SPM Controller............................................................................................................14
1.2.9. Vibration Isolation System...........................................................................................15
1.3. THEORY OF OPERATION OF SOLVER SNOM................................................................................... 15
1.4. TECHNICAL CHARACTERISTICS ....................................................................................................... 20
1.5. BASIC SAFETY MEASURES.............................................................................................................. 22
1.6. OPERATING CONDITIONS ................................................................................................................ 23
1.7. STORAGE AND TRANSPORT REGULATION ....................................................................................... 24
2. SETUP AND INSTALLATION............................................................................................................25
2.1. INSTALLING THE Z-SCANNER AND THE OBJECTIVE ......................................................................... 25
2.2. INSTALLING THE SCANNING STAGE ................................................................................................ 26
2.3. INSTALLING OF A SPECIAL SUPPORT ON THE MEASURING HEAD .................................................... 28
2.4. CABLE CONNECTIONS..................................................................................................................... 30
2.5. ASSEMBLY OF THE LASER MODULE ............................................................................................... 31
2.6. CONFIGURING THE CONTROL PROGRAM.......................................................................................... 35
2.7. POWERING SEQUENCE..................................................................................................................... 35
3. PREPARATION OF THE SOLVER SNOM FOR OPERATION ....................................................37
3.1. INSTALLATION OF THE PROBE INTO THE MEASURING HEAD........................................................... 37
3.2. PREPARATION AND INSTALLATION OF THE OPTICAL FIBER IN THE LASER MODULE....................... 40
3.3. SETTING UP THE TRANSMISSION MODE .......................................................................................... 42
3.4. SETTING UP THE REFLECTION MODE .............................................................................................. 45
4. MEASUREMENT PROCEDURE........................................................................................................47
4.1. INITIAL STATE ................................................................................................................................47
4.2. MAIN OPERATING PROCEDURES..................................................................................................... 47
4.3. SETTING OF THE INSTRUMENT CONFIGURATION............................................................................. 48
4.4. SELECTING THE MODE OF SCANNING .............................................................................................. 48
4.5. MOUNTING A SAMPLE .................................................................................................................... 48
4.6. ADJUSTING THE SCANNING STAGE SENSORS ................................................................................... 49
4.7. INSTALLATION OF THE MEASURING HEAD ON THE SCANNING STAGE ............................................ 51
4.8. SEARCH FOR RESONANCE FREQUENCY........................................................................................... 53
4.9. SETTING THE SIGNAL TUNE_FORK INITIAL LEVEL .......................................................................... 56
4.10. PROBE LANDING............................................................................................................................. 56
4.11. SETTING OF THE PHOTOMULTIPLIER MODULE PARAMETERS.......................................................... 58
4.12. SCANNING ...................................................................................................................................... 60
4.12.1. Setting of Scanning Parameters................................................................................... 60
4.12.2. Triggering of Scanning ................................................................................................63
4.12.3. Methods of Improving Image Quality ..........................................................................64
5. SAVING OF MEASUREMENT RESULTS........................................................................................65
6. TERMINATION OF MEASUREMENTS...........................................................................................66
Chapter 1. Basic Information
1. Basic Information
1.1. Purpose of the Solver SNOM
The Solver SNOM is a specialized SPM measurement system built on the Solver platform.
A SNOM measuring head lies in the basis of this system.
SNOM techniques are used to study near-s urface optical charact eristics (including
luminescent and spectral) of various object s with resolution m uch greate r th an the
diffraction lim it. The higher resolution is ga ined by exposing sam ples with light going
through a diaphragm whose aperture is m uch less than the wavelength of the radiation
detected. The surface un der study lies in th e near field of the diaphrag m (at distan ces of
about 10 nm).
The m ost advanced technologies used in th e design of the system and the powerful
software make the Solver SNOM easy to adapt it to a broad variety of research tasks and to
use it in research laboratories, universities and scientific centers. For exam ple, to study
biological o bjects, for optics quality c ontrol, to study light em itting se miconductor
structures, properties of nano- optical and integrated optics com ponents, to investigate
characteristics of nano-electronic elements and quantum dots spectra, in particular.
The Solver SNOM can be used to solve the following problems:
−Measure surface topography of the sample under investigation;
−Measure s urface optical prope rties (reflection and transm ission coefficients,
distributions of luminescent characteristics);
−Perform nano-lithography operations (inc luding optical lithography on photosensitive
samples and thermo-lithography).
1.2. Description of Main Components
Main components of the Solver SNOM
The following parts are included in the basis configuration of the Solver SNOM:
1. Inverted Optical Microscope (item 1.2.1 on page 6);
2. XY Scanning Stage (item 1.2.2 on page 7);
3. Z-scanner of the objective (item 1.2.3 on page 8);
4. SNOM Measuring Head (item 1.2.4 on page 9);
5. Optical Fiber Probe (item 1.2.5 on page 12);
6. Photomultiplier Modules (item 1.2.6 on page 13);
7. Laser Module (item 1.2.7 on page 14);
8. SPM Controller (item 1.2.8 on page 14);
9. Vibration Isolation System (item 1.2.9 on page 15).
5
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
Investigation of optical charac teristics with resolution b etter than the dif fraction lim it is
performed with a SNOM scanni ng measuring head equipped with an optical fiber probe.
The probing beam is coupled into the probe by means of a laser module. When running the
“Transmission Mode” optical scheme, the optical viewing system is used both to select a
region of the sample surface for investigation and to control the process of approach of the
probe to the sam ple. The exchangeable m ount of an original design m akes it possible to
obtain both SMOM im ages of the sam ple unde r study and its optical im ages using the
inverted m icroscope. The objective of the inverted m icroscope is located in the
exchangeable mount, which inco rporates systems of coarse and fine focusing. This gives
the opportunity to use high-resolution objectives (including immersion ones). In addition to
the system of coarse manual positioning of th e sample, the scanning stage incorpo rates a
system of precis ion XY position ing, which can be used for XY scanning. A vibration
isolation table equipped with a dynam ic vibration protec tion system also contributes to
getting high resolution during measurements.
1.2.1. Inverted Optical Microscope
The inverted optical microscope Olympus IX71 (Fig. 1-1) is used to obtain both SNOM (or
other SPM) im ages and ordinary optical im ages. This m icroscope incorporates an o ptical
system, which, in the case of trans parent sam ples, can be used for visual con trol of the
approach process and to read optical signals by means of a photomultiplier unit.
Fig. 1-1. Inverted optical microscope Olympus IX71
6
Chapter 1. Basic Information
1.2.2. XY Scanning Stage
The scanning stage (Fig. 1-2) is made of an aluminum alloy by electro-erosion processing.
It contains two m oveable fram es with flexible guidew ays. The guideways secure
translation of the outer f rame with respect to the fixed part of the stag e in the direction of
the longer part of the stage, this is the axis X. The inner frame can move on the guideways
in the Y direction. Translation of the frames is performed by a piezodriver through an arm-
type transmission device. The corresponding leve rs are engaged with the fra mes by means
of drawbars.
Special sensors are employed to determine the magnitude of translation of the piezodriver.
This m akes it possible to drive the fram es with high linearity, good repeatability and
minimize the hysteresis and crypt effects that accompany operations with piezo-ceramics.
The central part of the stage has an orifi ce which is used in the “Transm ission Mode”
scheme to transmit optical signals from the sample to the objective.
Fig. 1-2. Scanning Stage
1 – sample holder; 2 – spring clips; 3 – vacuum holder of the sample;
4 – pump pipe; 5 – spring; 6 – measuring head seats;
7 – micrometer screws; 8 – housing
The top part of the whole m echanism is enclos ed within housing 8. The sam ple is placed
on the sam ple holder 1 and it is fixed with spring clips 2 or vacuum holder 3. Spring 5
presses the measuring head, which is mounted on the stage, to micrometer screws 7. When
selecting a segm ent of the sam ple for invest igation, the m easuring head m oves over the
sample by means of micrometer screws 7.
7
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
Fig. 1-3. Adapter plate
The scanning stage is mounted on the adapter plate ( Fig. 1-3), which is m ounted on the
sample stage of the inverted microscope.
1.2.3. Z-scanner of the objective
When perform ing research on trans parent sam ples, th e pro be ligh t co mes out from the
probe and passes through the sample. Then it is c ollimated by the objective and is directed
at the entrance of the trinocular (o r photomultiplier) by means of the opt ical system of the
inverted microscope.
To achieve high quality im aging, the objective should be well focused onto the surface of
the sample. Fine focus is perform ed by means of a Z-scanner equipped with a piezo-drive
(Fig. 1-4). Displacement of the ob jective is measured by means of a sensor bu ilt into the
scanner. This scanner is m ade of an alum inum alloy by electro-eros ion processing. It is
screwed in to the revo lver head of the m icroscope ins tead of the objective, while the
objective itself is screwed into the scanne r either directly or through an adapter ( Fig. 1-5),
which is required in so me cases to place the focal plane of the ob jective into the plane of
the sample.
Fig. 1-4. Z-scanner Fig. 1-5. Adapter
8
Chapter 1. Basic Information
1.2.4. SNOM Measuring Head
The SNOM m easuring head ( Fig. 1-6) is u sed for both m easurements of surface
topography of the sam ple and for m easurements of its near-su rface o ptical p roperties.
Oscillation am plitude and phase of the pr obe can also be registered during these
measurements.
Fig. 1-6. Measuring head
1 – output orifice for the optical fiber; 2 – leveling posts; 3 – probe holder;
4 – housing; 5 – mounting plate; 6 – motorized legs
All elem ents of the SNOM m easurement head are assem bled on the mounting plate 5.
The scanner is contained within the housing 4. The capacitance sensors are fixed to the
bottom part of the scanner. The end of the scanner has a special holder for the optical fiber
probe 3. The top part of the housin g 4 has an output orifice 1 fo r the free end of the optical
fiber.
There are three leveling posts to secure inst allation, horizontal leveling and delivery of the
measuring head to the sam ple. Two of the m are ordinary screws, 2, with fastening nuts.
The third post is a micrometer screw driven by a stepper motor 6 (motorized leveling post),
which provides the motorized translation of the probe towards the sample.
The probe is fixed in the holder 1 ( Fig. 1-7) with spr ing clip s 2, w hich a lso se rve as
electrical contacts to acquire signal from the sensor. During installation of the sensor, the
optical fiber is put through the orifice 5. Th e scanner 3 provides scanning of a given XY
area of the sam ple by probe and it reads vari ations of the surface in the Z direction.
9
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
Observation of the probe tip both during the approach procedure a nd while se lecting the
area for measurement is available through a special groove in the protective case 4.
Fig. 1-7. Probe holder assembly
1 – probe holder; 2 – spring clips; 3 – bottom part of the scanner;
4 – protective case; 5 – optical fiber input orifice
Movements of the scanner in the XY plane are controlled by m eans of the capacitance
sensors (Fig. 1-8).
10
Chapter 1. Basic Information
Fig. 1-8. Functional schematics of the SNOM measuring head
A special optical attachm ent unit is used for measurem ents on non-transparent samples
(Fig. 1-9). Light radiation reflected from the sample is focused by the optical system of this
unit onto the receiving element of a photomultiplier module installed in it.
11
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
Fig. 1-9. Measuring head with the optical attachment unit
1.2.5. Optical Fiber Probe
Optical fiber probe ( Fig. 1-10) makes it possible to control the distance between the probe
tip and the sample and it is used to deliver laser beam to the sample surface.
Fig. 1-10. Optical fiber probe assembly
1 – quartz resonator; 2 – optical fiber; 3 – contact areas
The probe consists of the follow ing parts: quartz resonator 1, single-m ode optical
fiber 2 glued to the resonator and the textolit e base with contact ar eas 3. The end of the
fiber, which is fixed to the quartz resonator w ith glue, is sharpened by chem ical etching or
other m ethods so that a tip w ith the radius of curvature of about 50÷100 nm is form ed.
A m etal lay er is depos ited on the end of the fiber so that the very tip, of 50÷100 nm
diameter, remains clear.
The sensor used to control the dis tance between the tip and the sam ple is a U-shape quartz
resonator (tuning fork). The sh arpened end of the optical fi ber is glued to one of the
12
Chapter 1. Basic Information
resonator’s console so that it comes out by 0.5÷1.0 mm. Th e force interaction occurs
between this sharpened end (probe tip) and the surface under investigation.
Signal generated by the quartz resonator is received through the contact areas.
1.2.6. Photomultiplier Modules
Photomultiplier m odules are in tended for conve rting op tical radiation acquired fro m the
sample into electrical signals.
An overall view of the photomultiplier modules is given in Fig. 1-11.
a) Photomultiplier module for installation in
the optical microscope
b) Photomultiplier module for installation on the
optical attachment
Fig. 1-11. Overall view of the photomultiplier modules
1 – photomultiplier; 2 – cable for connecting to the controller; 3 – shutter
#NOTE. Photomultipliers included in your set might be different from those
shown in Fig. 1-11.
*ATTENTION! Photomultiplier is a photosensitive device. To avoid permanent
damage and earlier degradation, do not expose it to high intensity radiation
even if it is not connected. Open the shutter only for measurements. Avoid
overloading the photomultiplier.
13
Solver SNOM. Scanning Near-Field Optical Microscope. Instruction Manual
1.2.7. Laser Module
The laser m odule is intended to couple laser ra diation into the optical fiber. An overall
view of the module equipped with a solid-state 532 nm laser is given in Fig. 1-12.
Fig. 1-12. Laser module
1 – base; 2 – positioning stage; 3 – fiber mounting stage;
4 – objective; 5 – laser source; 6 – power supply
The m odule incorporates the base 1. This ba se is used for mounting the laser source 5
and the positioning stage 2 with a microscope objective 4 and the fiber mounting stage 3.
#NOTE. The laser module can be configured to contain lasers of various types
(gas, solid-state), different output power and operating on different wavelengths
(see technical documentation provided).
1.2.8. SPM Controller
The SPM controller provides control of th e probe m easurement system . Its m ain
functions are:
−Processing signals received from measuring heads;
−Conversion of signals generated by the computer control program Nova;
−Generating signals for scanners and probe;
−Auxiliary devices control.
The m ore detailed description of the SPM c ontroller is p rovided in the m anual “Control
Electronics”.
14
The sample (normally placed on a su bstrate) is placed on the sample stage. The measuring
head is mounted on the scanning stage. Then, using the m otorized leveling post, the probe
is landed onto the sam ple at the distance defined by the param eter Set Point and, then, the
scanning procedure starts in the plane of the sample.
The optical fiber probe is fixed to the scanne r, which is ins talled in side the m easuring
head. A piezo vibrato r is located at the place where the probe is fixe d to the sca nner. It
oscillates at the resonance frequency of the system consisting of the probe, quartz resonator
and probe holder. Signal is read from the contacts of the quartz resonator. It is proportional
to the oscillation am plitude of the resonator. During the approach of the probe to the
sample surface, th e res onance freq uency of th e system changes due to the influence of
atomic interaction s between the probe tip an d the surface ( Shear Force Microscopy
(ShFM)). T his induces a rapid drop of the oscillation am plitude and an alteration o f the
oscillation phase of the quartz resonator. Consequently, the m agnitude of the signa l
acquired from the resonator changes. These variations are detected by the lock-in amplifier
incorporated into the feedback system, which drives the piezo tube of the scanner along the
Z axis. Thu s the feedback system keeps the magnitude of interaction between the probe
and sam ple constant during scanning. The valu e of this m agnitude of interaction can be
indirectly set by m eans of the param eter Set Point in the program of c omputer control of
scanning. T he driving signal applied to the Z -scanner is used as th e source of data to
reproduce surface topography of the sample.
1.3. Theory of Operation of Solver SNOM
Scanning probe m icroscope system s are vulnera ble to external vibrations, which distort
images of surfaces and also deterio rate their quality. A special v ibration isolation system
(Fig. 1-13) equipped with a system of dynamic vibration isolation is utilized to protect this
system from external vibrations.
1.2.9. Vibration Isolation System
15
Fig. 1-13. Vibration isolation system
Chapter 1. Basic Information
Other manuals for Solver SNOM
1
Table of contents
Other NT-MDT Microscope manuals
Popular Microscope manuals by other brands
Ken A Vision
Ken A Vision Video Flex® except 2000 series manual
Denville Scientific
Denville Scientific M2100 Series Operation manual
Levenhuk
Levenhuk Discovery Atto user manual
National Geographic
National Geographic 40 1024X manual
Trends UK
Trends UK Discovery TDK34 manual
LW Scientific
LW Scientific Mi5 instruction manual
