Chapter 6
Absorption-Based Far-Field Label-Free
Super-Resolution Microscopy
Chen Li and Ji-Xin Cheng
Abstract Materials absorption, which happens in all light–matter interactions,
has been studied systematically and inspires various chemical-specific measurement methods for extensive non-fluorescent species. In this chapter, we review
recent achievements of far-field label-free super-resolution microscopy (LFSRM)
that deploys materials absorption to provide the contrast. In the linear absorption
modalities, samples convert photon energy to heat efficiently, which turns the photothermal detection with single-molecule sensitivity into possible. The photothermal
microscope breaks the diffraction limit of the excitation beam by probing the localized thermal lens effect using a shorter-wavelength beam. In the nonlinear absorption modalities, one pump beam profile could be engineered to doughnut shape and
reduce the size of the nonlinear region, which helps achieve sub-diffraction resolution. Both mechanisms use the intrinsic vibrational or electronic absorption of
molecules, through which different species are readily discriminated. Owing to the
chemical specificity and high sensitivity, this label-free LFSRM provides unique
advantages in various materials and in biomedical applications, including nanomaterial inspection and in vivo imaging of living cells and organisms.
6.1 Introduction to Absorption-Based Far-Field Label-Free
Super-Resolution Microscopy
The development of biological and biomedical sciences in the twentieth century has
expedited the growth of far-field microscopy, which enabled numerous intracellular
studies with minimal invasion [1]. However, traditional far-field microscopy cannot
focus light onto a spot that is smaller than the diffraction limit [2]. As a consequence,
C. Li
Department of Chemistry, Purdue University, West Lafayette, IN 47906, USA
J.-X. Cheng (B)
Boston University Photonics Center, Boston, MA 02215, USA
e-mail: jxcheng@bu.edu
URL: http://sites.bu.edu/cheng-group/
© Springer Nature Switzerland AG 2019
V. Astratov (ed.), Label-Free Super-Resolution Microscopy,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-3-030-21722-8_6
137
Absorption-Based Far-Field Label-Free
Super-Resolution Microscopy
Chen Li and Ji-Xin Cheng
Abstract Materials absorption, which happens in all light–matter interactions,
has been studied systematically and inspires various chemical-specific measurement methods for extensive non-fluorescent species. In this chapter, we review
recent achievements of far-field label-free super-resolution microscopy (LFSRM)
that deploys materials absorption to provide the contrast. In the linear absorption
modalities, samples convert photon energy to heat efficiently, which turns the photothermal detection with single-molecule sensitivity into possible. The photothermal
microscope breaks the diffraction limit of the excitation beam by probing the localized thermal lens effect using a shorter-wavelength beam. In the nonlinear absorption modalities, one pump beam profile could be engineered to doughnut shape and
reduce the size of the nonlinear region, which helps achieve sub-diffraction resolution. Both mechanisms use the intrinsic vibrational or electronic absorption of
molecules, through which different species are readily discriminated. Owing to the
chemical specificity and high sensitivity, this label-free LFSRM provides unique
advantages in various materials and in biomedical applications, including nanomaterial inspection and in vivo imaging of living cells and organisms.
6.1 Introduction to Absorption-Based Far-Field Label-Free
Super-Resolution Microscopy
The development of biological and biomedical sciences in the twentieth century has
expedited the growth of far-field microscopy, which enabled numerous intracellular
studies with minimal invasion [1]. However, traditional far-field microscopy cannot
focus light onto a spot that is smaller than the diffraction limit [2]. As a consequence,
C. Li
Department of Chemistry, Purdue University, West Lafayette, IN 47906, USA
J.-X. Cheng (B)
Boston University Photonics Center, Boston, MA 02215, USA
e-mail: jxcheng@bu.edu
URL: http://sites.bu.edu/cheng-group/
© Springer Nature Switzerland AG 2019
V. Astratov (ed.), Label-Free Super-Resolution Microscopy,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-3-030-21722-8_6
137