Chapter 7
Opto-spintronics
7.1 Introduction: What Is Opto-spintronics?
Opto-spintronics is an emerging and fascinating branch of spintronics where light
is used for the study and/or control of electron spin. Opto-spintronics combines the
effect of light with the spin of charge carriers and hence, fast and accurate control of
electron spins is expected. We can say that opto-spintronics is an inter-disciplinary
field of overlapping region of optics, electronics and magnetics (shown in Fig. 7.1).
• Spintronics is a spin-dependent phenomenon applied to electronic devices.
• Optoelectronics is the study and application of electronic devices that interact
with light.
• Magnonics is the study of spin waves and magnetism. Opto-magnonics is
manipulating spin waves with light pulses.
This emerging field of spintronics has received tremendous momentum as
femtosecond laser has the capability of fastest change in magnetic state of matter.
Now let us see what is femtosecond laser and why it is so important?
7.2 What Is so Special About Femtosecond Laser?
A femtosecond laser is one kind of ultrashort laser where light is emitted in
femtosecond domain, i.e., of the order of 10
−15 s (see Fig. 7.2). Femtosecond laser
is technologically important for its wide use in automobile, medical instrumentation and micro-electronics industries. It has also triggered the ultrafast controlling of
magnetic materials.
Some special features of this laser are mentioned below
• Being very short optical pulse, it bears the ability of instant excitation.
• Monitoring of excited state can be done with greater temporal resolution (≈12–
50 fs).
© Springer Nature Singapore Pte Ltd. 2021
P. Dey and J. N. Roy, Spintronics,
https://doi.org/10.1007/978-981-16-0069-2_7
163
Opto-spintronics
7.1 Introduction: What Is Opto-spintronics?
Opto-spintronics is an emerging and fascinating branch of spintronics where light
is used for the study and/or control of electron spin. Opto-spintronics combines the
effect of light with the spin of charge carriers and hence, fast and accurate control of
electron spins is expected. We can say that opto-spintronics is an inter-disciplinary
field of overlapping region of optics, electronics and magnetics (shown in Fig. 7.1).
• Spintronics is a spin-dependent phenomenon applied to electronic devices.
• Optoelectronics is the study and application of electronic devices that interact
with light.
• Magnonics is the study of spin waves and magnetism. Opto-magnonics is
manipulating spin waves with light pulses.
This emerging field of spintronics has received tremendous momentum as
femtosecond laser has the capability of fastest change in magnetic state of matter.
Now let us see what is femtosecond laser and why it is so important?
7.2 What Is so Special About Femtosecond Laser?
A femtosecond laser is one kind of ultrashort laser where light is emitted in
femtosecond domain, i.e., of the order of 10
−15 s (see Fig. 7.2). Femtosecond laser
is technologically important for its wide use in automobile, medical instrumentation and micro-electronics industries. It has also triggered the ultrafast controlling of
magnetic materials.
Some special features of this laser are mentioned below
• Being very short optical pulse, it bears the ability of instant excitation.
• Monitoring of excited state can be done with greater temporal resolution (≈12–
50 fs).
© Springer Nature Singapore Pte Ltd. 2021
P. Dey and J. N. Roy, Spintronics,
https://doi.org/10.1007/978-981-16-0069-2_7
163